Tutors Answer Your Questions about Probability-and-statistics (FREE)
Question 282486: You have seven cards. One is picked without looking what is the probability?
Answer by Alan3354(8274)   (Show Source):
Question 282405: Find the minimum and maximum possible areas for a rectangle measuring 4.15 cm by 7.34 cm.
Answer by richwmiller(3756)  (Show Source):
Question 282343: f you roll a die 38 times and 12 of the rolls result in a "5," what empirical probability was observed for the event "5"?
Answer by edjones(4080)  (Show Source):
Question 282029: Question:
Decide whether the distribution is a probability distribution. If it is not a probability distribution, identify the property that is not satisfied.
x P(x)
1 0.038
2 0.200
3 0.445
4 0.294
Answer:
NO
All probabilities are greater than or equal to 0 and less than or equal to 1 but
The sum of all probabilities is not 1
Answer by Mathematicians(78)  (Show Source):
You can put this solution on YOUR website!It looks like you have the answer. You first have to check to make sure all x values are greater than or equal to 0. Which that satisfies. The only other condition is that the summation of all p(x) is equal to 1. You will see that summation of P(x) does not equal to 1 therefore it is not a probability distribution.
Question 282006: Suppose I roll a fair die two times..
How many different samples are there?
Answer by solver91311(6137)  (Show Source):
You can put this solution on YOUR website!
36
1 way to make 2
2 ways to make 3
3 ways to make 4
.
.
.
6 ways to make 7
.
.
.
2 ways to make 11
1 way to make 12
1 plus 2 plus ... plus 6 plus 5 plus ... plus 1 = 36
John
Question 282001: Suppose you have 4 nickels, 6 dimes, and 4 quarters in your pocket. If you draw a coin randomly from your pocket what is the probability that
a. you will draw a dime
b. you will draw a nickel
c. you will draw a quarter
Here is what I have so far
a. 6/14 43%
b. 4/14 29%
c. 4/14 29%
Answer by brucewill(28) (Show Source):
Question 281972: The graduate selection committee wants to select the top 10% of applicants. On a standardized test with a mean of 500 and a standard deviation of 100, what would be the cutoff score for selecting the top 10% of applicants, assuming that the standardized test is normally distributed?
Answer by stanbon(29602) (Show Source):
You can put this solution on YOUR website!The graduate selection committee wants to select the top 10% of applicants. On a standardized test with a mean of 500 and a standard deviation of 100, what would be the cutoff score for selecting the top 10% of applicants, assuming that the standardized test is normally distributed?
---------------------------------------------------
Find the z-value that has right-tail of 10%.
z = invNorm(0.90) = 1.2816
--------------------------------
Find the x-value that corresponds to that z-score:
x = zs + u
x = 1.2816*100 + 500
x = 128.16 + 500
x = 628.16
=================
Cheers,
Stan H.
Question 281791: With Binomial Distributions and Probability:
In a lottery, each ticket buyer has a 1 in 10 chance of winning a prize. If Steve buys 10 tickets, what is the probability that he will win at least 1 prize? How do you work this problem out?
Answer by stanbon(29602) (Show Source):
You can put this solution on YOUR website!With Binomial Distributions and Probability:
In a lottery, each ticket buyer has a 1 in 10 chance of winning a prize. If Steve buys 10 tickets, what is the probability that he will win at least 1 prize? How do you work this problem out?
-------------------------------
Binomial Problem:
n = 10 ; p = 1/10
---
P(win at least 1) = 1 - P(win none)
----
P(win at least 1) = 1 - (0.9)^10
---
P(win at least 1) = 1 - 0.3487 = 0.6513
========================================
Cheers,
Stan H.
Question 281884: A number from 14 to 22 is drawn at random probability and even number
Answer by Fombitz(2609)  (Show Source):
Question 281856: A psychologist would like to determine whether there is a relation between depression and aging. It is known that the general population averages µ = 40 on a standardized depression test. The psychologist obtains a sample of n = 36 individuals who are all older than the age of 70. The average depression score for this sample is M = 44.5 with SS = 5040. On the basis of this sample, can the psychologist conclude that depression for elderly people is significantly different from depression in the general population? Use a two-tailed test at the .05 level of significance.
Answer by stanbon(29602) (Show Source):
You can put this solution on YOUR website!A psychologist would like to determine whether there is a relation between depression and aging. It is known that the general population averages µ = 40 on a standardized depression test.
The psychologist obtains a sample of n = 36 individuals who are all older than the age of 70. The average depression score for this sample is M = 44.5 with SS = 5040.
On the basis of this sample, can the psychologist conclude that depression for elderly people is significantly different from depression in the general population? Use a two-tailed test at the .05 level of significance.
---------------------------
Ho: u = 40
Ha: u is not equal to 40
----------------
test stat: t(44.5) = (44.5-40)/[s/sqrt(36)]
---
Note: You say SS=5040. You did not post the standard
deviation of the population or of the sample.
---
Cheers,
Stan H.
Question 281562: In Dallas, some fire trucks were painted yellow (instead of red) to heighten their visibility. During a test period, the fleet of red fire trucks made 153,348 runs and had 20 accidents, while the fleet of yellow fire trucks made 135,035 runs and had 4 accidents. At α = .01, did the yellow fire trucks have a significantly lower accident rate? (a) State the hypotheses. (b) State the decision rule and sketch it. (c) Find the sample proportions and z test statistic. (d) Make a decision. (e) Find the p-value and interpret it. (f ) If statistically significant, do you think the difference is large enough to be important? If so, to whom, and why? (g) Is the normality assumption fulfilled? Explain.
Answer by stanbon(29602) (Show Source):
You can put this solution on YOUR website!In Dallas, some fire trucks were painted yellow (instead of red) to heighten their visibility.
During a test period, the fleet of red fire trucks made 153,348 runs and had 20 accidents, while the fleet of
-------
p-hat(red) = 20/153,348 = 1.304x10^-4
------------
yellow fire trucks made 135,035 runs and had 4 accidents.
p-hat(yellow) = 4/135035 = 2.9622x10-5
-------------------
At α = .01, did the yellow fire trucks have a significantly lower accident rate?
One-tail z-test: Critical value = 2.326
(a) State the hypothesis.
Ho: p(red)-p(yellow) = 0
Ha: p(red)-p(yellow) < 0
-------------------------------
(b) State the decision rule and sketch it.
? Not sure what is meant by this.
-------------------------------
(c) Find the sample proportions and z test statistic.
Test statistic:
---
Note: p-bar= (4+20)/(153348+135035) = 8.3223x10^-5;q-bar=1-p-bar
-----------------------
Test statistic
z(1.0078x10^-4) = 1.0078x10^-4/sqrt[(p-bar)(q-bar)/n1 + (p-bar)(q-bar)/n2]
= 2.9610
(d) Make a decision.
Since the test statistic is greater than the critical value, reject Ho.
p(red) is not equal to p(yellow)
------------------------------------------
(e) Find the p-value and interpret it.
p-value = 0.0015 ; Only 0.15% of test results could have provided stronger
evidence for rejecting Ho.
-------------------------
(f ) If statistically significant, do you think the difference is large enough to be important? If so, to whom, and why?
I'll leave that to you
--------------------
(g) Is the normality assumption fulfilled? Explain.
Show that p(red)n1>5, q(red)n1>5
and p(yellow)n2>5, q(yellow)n2>5
=======================================
Cheers,
Stan H.
Question 281709: A student takes a 20-question, multiple choice exam with five choices for each question and guesses on each question. Assuming for each question only one of the five choices is correct, what is the mean number of questions the student could get correct by guessing?
Answer by stanbon(29602) (Show Source):
You can put this solution on YOUR website!A student takes a 20-question, multiple choice exam with five choices for each question and guesses on each question. Assuming for each question only one of the five choices is correct, what is the mean number of questions the student could get correct by guessing?
--------------------------------------
Binomial Problem:
n = 20 ; p = 1/5
----
mean = np = (1/5)20 = 4
---------------------------------
Cheers,
Stan H.
Question 281715: Between the years on 1901 and 2003. suppose that the nobel prize between 1901 and 2003 was chosen at random what is the probability the prize goes to japan?
country winners
usa 219
uk 76
germany 63
france 25
soviet 12
japan 8
other countries 91
Answer by Alan3354(8274) (Show Source):
You can put this solution on YOUR website!The total is 494.
Japan won 8 of them.
8/494 =~ 0.01619 or 1.16% of the prizes
-----------------------
That's not a probability, it's a certainty, it happened.
Question 281627: several factors influence the value obtained for a t statistic. Some factors affact the numerator of the t statistic and others influence the size of the estimated standard error in the denominator. For each of the following, indicate whether the factor influences the numerator or denominator of the t statistic and determine whether the effect would be to increase the value of t (farther from zero) or decrease the value of t ( closer to zero ). In each case, assume that all other factors remaine constant .
a - Increase the variability of the scores.
b - Increase the number of scores in the sample.
c - Increase the difference between the sample mean and the population mean.
Answer by stanbon(29602) (Show Source):
You can put this solution on YOUR website!several factors influence the value obtained for a t statistic. Some factors affact the numerator of the t statistic and others influence the size of the estimated standard error in the denominator. For each of the following, indicate whether the factor influences the numerator or denominator of the t statistic and determine whether the effect would be to increase the value of t (farther from zero) or decrease the value of t ( closer to zero ). In each case, assume that all other factors remaine constant .
---
General Form:
t(x) = (x-u)/[s/sqrt(n)]
-----------------------------
a - Increase the variability of the scores. As s increases, t decreases.
---------------------------------------
b - Increase the number of scores in the sample. As n increases, t increases.
-----------------------------
c - Increase the difference between the sample mean and the population mean.
As the difference increases t increases.
=============================================
Cheers,
Stan H.
Question 281549: The problem is: A student scored 80 for an English exam and 72 for a History exam. If the class scores were normally distributed with a mean and standard deviation for English of 75 and 8 respectively, and for History 60 and 15 respectively, in which subject did the student achieve a higher standard, and what percentage of others achieved higher marks in each subject?
Answer by Mathematicians(78) (Show Source):
You can put this solution on YOUR website!You want to find the Z score for each subject. You can recall, the higher z is, the smaller the graph goes which symbolize a higher tier in ranking. For a higher ranking, you want to take the greatest positive z
So, to calculate z score, you would calculate  where x is the data, M is the mean, and s is standard deviation.
For English:
For History:
 => History achieved higher standard.
Now we need to find what percentage of others achieved higher marks in each subject. Unfortunately Z tables calculate Z values different and for that I cannot tell you how to use a Z table.
We calculated Z = 5/8 for English
We want to find P(z > 5/8)
You may need to do .5 - P(z = 5/8) or 1 - P(z = 5/8) depending on your Z table
Same thing with history except:
You may need to do .5 - P(z = 4/5) or 1 - P(z = 4/5) depending on your Z table.
Good luck!
Question 281545: The problem is: The mean contents of bottles of a certain brand of soft drink is 310 ml. with a standard deviation of 5 ml.
a) What percentage of bottles would contain betwen 300 and 310 ml of contents?
b) What percentage of bottles would contain at least 304 ml of contents?
c) What is the probability of a bottle containing less than 300 ml of content?
Answer by Mathematicians(78) (Show Source):
You can put this solution on YOUR website!Unfortunately I do not have a Z table, not to mention different Z tables calculate things differently. with me and it has been ages since I took statistics, but this should be the correct way to solve this problem.
You have the formula:
 Where X is the data, M is the mean, and S is the standard deviation. Z is the Z score it corresponds with.
a) our data is 300 and 310 and we want it in between. Well, we know 310 is the mean so that is when z = 0. We do not need to check this, we need to check 300.
Depending on your Z table, Z = -2 should correspond with some decimal. That is your answer.
b) with this one, you want to calculate z > 304. Once again, depending how your Z table looks at it, you will either have to do 1 - P(x=304) or .5 + p(x = 304)
We can begin calculating Z:
I can't really tell you how your Z table calculates probability because I have had two different Z tables in a couple different classes a few years ago.
Question 281458: Which of the following statements are correct?
a.A normal distribution is any distribution that is not unusual.
b.The graph of a normal distribution is bell-shaped.
c.If a population has a normal distribution, the mean and the median are not equal.
d.The graph of a normal distribution is symmetric.
Answer by brucewill(28) (Show Source):
You can put this solution on YOUR website!a.A normal distribution is any distribution that is not unusual.
This is not necessarily true; not unusual does not directly mean a "normal distribution".
b.The graph of a normal distribution is bell-shaped.
By definition, this is true.
c.If a population has a normal distribution, the mean and the median are not equal.
This may or may not be true; mean and median are different measures of central tendancy.
d.The graph of a normal distribution is symmetric.
Again, by definition, this is true.
Question 281474: a sample of the reading scores of 29 fifth gtaders has a mean of x(with the bar on top of the x)=83 and a population standard deviation of r=10.5.
a. Find 99% confidence interval for the population mean scores of all fifth graders on this test.
b. How big should the sample size be for the margin of error to be no larger that 3.5?
c. 99% confidence interval if the sample was 29 fifth graders and you were given the sample standard deviation s=10.5 instead of the population standard deviation?
Answer by stanbon(29602) (Show Source):
You can put this solution on YOUR website!a sample of the reading scores of 29 fifth gtaders has a mean of x(with the bar on top of the x)=83 and a population standard deviation of r=10.5.
a. Find 99% confidence interval for the population mean scores of all fifth graders on this test.
---
xbar = 83 ; s = 10.5, so s-hat = 10.5/sqrt(29) = 1.9498
invT(0.995,with df=28) = 2.7633
So, standard error for the population means = 2.7633*
---
95% CI: 83-2.7633 < u < 83+2.7633
95% CI: 80.2367 < u < 85.7633
=========================================
b. How big should the sample size be for the margin of error to be no larger that 3.5?
n = [1.96*10.5/3.5]^2 = 34.57
Rounding up: n = 35
==============================
c. 99% confidence interval if the sample was 29 fifth graders and you were given the sample standard deviation s=10.5 instead of the population standard deviation?
Question 281391: 5. Twenty of the houses on a street receive cable t.v. and seven do not. A researcher studying the amount of time that people watch t.v. intends to visit five of the houses that receive cable t.v and two that do not. How many such selections of houses are there
Answer by edjones(4080) (Show Source):
Question 281449: I am about to ask MTV viewers the following question: "Do you regularly watch MTV's Beavis and Butthead?" Last week I asked 100 of my friends the same question and 35 of them said yes.
How many actual viewers must be surveyed to be 95% confident that the estimate of the viewership is in error by at most 3%? (Assume 100% response rate.)
What would be your answer if I had not surveyed any of my friends?
Please show details of your work.
Answer by stanbon(29602) (Show Source):
You can put this solution on YOUR website!How many actual viewers must be surveyed to be 95% confident that the estimate of the viewership is in error by at most 3%? (Assume 100% response rate.)
------------------
n = [zs/E]^2
n = [1.96*s/0.03]^2
----
You would need to know the standard deviation
of the distribution.
===============
Cheers,
Stan H.
Question 281392: Multiply 234 • 57 using lattice multiplication
Answer by Inkyvoyd(17) (Show Source):
Question 281394: Simplify each of the following, if possible. Write your answers in the exponential form a^b
A. 2^4*2^3*2^8
Answer by richwmiller(3756) (Show Source):
You can put this solution on YOUR website!1-These prob1ems have nothing to do with probability nor statistics.
2-There is more than one problem
3-They are similar
amazing you were able to break three rules at once.
Question 281388: Suppose that the following game is played. A woman rolls a fair die. If she rolls a 1 or 6, she loses $1. If she rolls a 2 or a 5, she loses $2. If she rolls a 3 or 4, she wins $9. What is the expected value of the game?
Answer by Mathematicians(78) (Show Source):
You can put this solution on YOUR website!I would first set up a table where P(x) is the probability for event x and the outcome if x happens (or Y). For example, your question would start like this. Some basic information is that a die has 6 sides, therefore a fair die has a probability of landing 1/6 on each side.
X -- P(x) -- Y
1 -- 1/6 -- -$1
2 -- 1/6 -- -$2
3 -- 1/6 -- +$9
4 -- 1/6 -- +$9
5 -- 1/6 -- -$2
6 -- 1/6 -- -$1
When you have a table like this, you want to multiply each P(x) * y and add them up.
So in your case we would get:
1/6 * -$1
+1/6 * -$2
+1/6 * +$9
+1/6 * +$9
+1/6 * -$2
+1/6 * -$1
= $(-1/6 - 2/6 + 9/6 + 9/6 - 2/6 - 1/6) (It is helpful if you keep the same denominator)
= + $12/6 = $2
$2 is the expected value. What this represents is that if you somehow played infinite games, you would win an average of $2 per game.
Question 281358: A.The diameters of bolts produced by a certain machine are normally distributed with a mean of U=0.30 inches and a standard deviation, r=0.042, inches. What percentage of bolts will have a diameter greater than 0.320 inches?
B.If 11 bolts are selected, what percentage of bolts will have a mean diameter greater than 0.32 inches?
Answer by stanbon(29602) (Show Source):
You can put this solution on YOUR website!A.The diameters of bolts produced by a certain machine are normally distributed with a mean of U=0.30 inches and a standard deviation, r=0.042, inches. What percentage of bolts will have a diameter greater than 0.320 inches?
------------------
z(0.320) = (0.320-0.300)/0.42 = 0.0476
P(x > 0.32) = P(z > 0.0476) = 0.4812 = 42.12%
---------------------------------------------------
B.If 11 bolts are selected, what percentage of bolts will have a mean diameter greater than 0.32 inches?
z(0.32) = (-.320-0.300)/[0.42/sqrt(11)] = 0.1579
P(xbar > 0.32) = P(z > 0.1579) = 0.4373 = 43.73%
===================================================
Cheers,
Stan H.
Question 281350: the price of the orchestra level tickets were $125. Balcony tickets were $70. A total of 195 tickets were sold for $26650. Determine the number of orchestra level tickets and the number of balcony level tickets sold.
Answer by oberobic(498) (Show Source):
You can put this solution on YOUR website!b = number of balcony tickets sold
o = number of orchestra tickets sold
.
b + o = 195 :: given
or,
b = 195 - o and o = 195-b
.
125o = value of the orchestra tickets sold
70b = value of the balcony tickets sold
.
125o + 70b = 26650 :: given
.
substitute b = 195 - o:
.
125o + 70(195 - o) = 26650
125o + 13650 - 70o = 26650
,
collect and simplify
.
125o - 70o = 26650 - 13650
55o = 13000
o = 236.36
.
That is an odd result because it calls for selling a fraction of a ticket, and it calls for selling more than 195 tickets.
.
If ONLY orchestra tickets were sold @ $125 each, then that would be 213.2 tickets, which is more than 195.
.
So there appears to be something wrong with your problem statement.
.
Done
Question 281293: The equation y = -1777x + 27,153 can be used to predict the number of gun deaths in the U.S. x years after 2000, that is, x=0 corresponds to 2000, x=3 corresponds to 2003, x=6 corresponds to 2006, and so on. Predict the number of gun deaths in 2006 and 2007. In what year will the number of gun deaths be 12,937?
The predicted gun deaths in 2006 will be ___
The predicted gun deaths in 2007 will be ___
The predicted number of gun deaths will be 12,937 in the year___
Answer by stanbon(29602) (Show Source):
You can put this solution on YOUR website!The equation y = -1777x + 27,153 can be used to predict the number of gun deaths in the U.S. x years after 2000, that is, x=0 corresponds to 2000, x=3 corresponds to 2003, x=6 corresponds to 2006, and so on. Predict the number of gun deaths in 2006 and 2007. In what year will the number of gun deaths be 12,937?
The predicted gun deaths in 2006 will be -1777*6+27,153 = 16491
The predicted gun deaths in 2007 will be -1777*7+27,153 = 14714
The predicted number of gun deaths will be 12,937 in the year___
Solve -1777x+27,153 = 12,937 for "x":
-1777x = -14216
x = 8
---
Year: 2008
====================
Cheers,
Stan H.
Question 281279: Three cards are drawn from an ordinary deck of cards one by one without replacement. Find the probability of the following: a) Getting all Jacks b) Getting an Ace, a King and a Queen in order c) Getting an club-a spade and a heart in order d) Getting three clubs.
Answer by stanbon(29602) (Show Source):
You can put this solution on YOUR website!Three cards are drawn from an ordinary deck of cards one by one without replacement.
Find the probability of the following:
a) P(Getting all Jacks) = 4C3/52C3
-------------------------------------------
b) P(Getting an Ace) = 1-P(no aces) = 1-[48C3/52C3]
-------------------------------------------
a) P(King and a Queen in order) = (4/52)(4/51)
-------------------------------------------
c) P(Getting an club-a spade and a heart in order) = (13/52)(13/39)(13/26)
-------------------------------------------
d) P(Getting three clubs) = 13C3/52C3
----------------------------------------------
Cheers,
Stan H.
Question 281268: In a bumper test, three types of autos were deliberately crashed into a barrier at 5 mph, and the resulting damage (in dollars) was estimated. Five test vehicles of each type were crashed, with the results shown below. Research question: Are the mean crash damages the same for these three vehicles? Crash1
Crash Damage ($)
Goliath Varmint Weasel
1,600 1,290 1,090
760 1,400 2,100
880 1,390 1,830
1,950 1,850 1,250
1,220 950 1,920
Answer by stanbon(29602) (Show Source):
You can put this solution on YOUR website!Five test vehicles of each type were crashed, with the results shown below. Research questions: (a) Are the mean crash damages the same or significantly different among these three vehicles? (b) Are there any significant differences between pairs of groups? What test did you use? Explain.
Crash Damage in Dollars
Goliath
1100
750
970
1000
850
Varmint
1290
1400
1390
1850
1100
Weasel
1100
1500
1000
1250
1920
---------------------------
Ho: the means are all equal
Ha: at least one of the means is different
-----------------
I ran an ANOVA test against the three lists of data
and go the following results:
test statistic : F = 4.3638
p-value : 0.0377
-------------------------
Conclusion: Fail to reject Ho if alpha is 5% but reject Ho if alpha=1%.
-------------------------
Further testing could reveal which mean(s) is higher or lower if you
reject Ho.
====================================
Cheers,
Stan H.
Question 281095: Two dice are rolled and the sum of the two numbers that up is recorded. Find the probability that the sum of the two numbers is:
a) > 8
b) more than 3 but less than 8
c) exactly 6
Answer by edjones(4080) (Show Source):
You can put this solution on YOUR website!Let n=sum of the 2 dice and t=number of time that number is expected to come up in 36 rolls of the dice.
n=t
2 1
3 2
4 3
5 4
6 5
7 6
8 5
9 4
10 3
11 2
12 1
.
>8 is 4+3+2+1=10
10/36 probability
.
You can do the other two.
.
Ed
Question 281096: Edwin and Derek are archers. The probability that Edwin successfully hits a target is 0.7. The probability that Derek successfully hits a target is 0.6. Whenever they both shoot at a target, what is the probability that:
a) only one of them is successful
b) at least one of them is successful?
Answer by edjones(4080) (Show Source):
You can put this solution on YOUR website!Prob that both will miss=0.3 * 0.4=.12
Prob that both will hit = 0.7 * 0.6 = .42
a) 1-(.42+.12)=.46 prob only one of them is successful.
b) 1-.12=.88 prob at least one is successful.
.
Ed
Question 281141: You own 7 pairs of jeans and are taking 6 of them on vacation. In how many ways can you choose 6 pairs of jeans from the 7?
Answer by richwmiller(3756) (Show Source):
Question 281150: A question has five multiple-choice answers. Find the probability of guessing an incorrect answer.
Answer by Fombitz(2609) (Show Source):
You can put this solution on YOUR website!Five possible choices.
Only one is correct.
The probability of guessing incorrectly would be the number of wrong choices divided by the number of choices.
Question 281134: In a binomial distribution, n=25 and p=0.432
A.Show your work to find a save the mean and standard deviation of this binomial distribution.
B.Find the probability that x<=14.
Answer by stanbon(29602) (Show Source):
You can put this solution on YOUR website!In a binomial distribution, n=25 and p=0.432
A.Show your work to find a save the mean and standard deviation of this binomial distribution.
---
mean = np = 25*0.432 = 10.8
std = sqrt(npq) = sqrt(10.8*0.568) = 2.4768
---------------------------------------------------
B.Find the probability that x<=14.
Note: If this is binomial x should be a whole number.
What is the meaning of your "x"?
---------------------------------------------------
Cheers,
Stan H.
Question 281113: You throw a bean bag at a wall with 9 colored squares, each with an area of 1/9 ft^2. If you hit a square, you win a prize. The area of the wall is 45 ft^2. What is the probability that you will win a prize ? Answer in units of %.
Answer by edjones(4080) (Show Source):
Question 281115: suppose you have 225 square tiles, all the same size. you can tile one surface using all the tiles. how could you tile more than one square surface using all the tiles no surface can have only one tile
Answer by edjones(4080) (Show Source):
You can put this solution on YOUR website!Factor 225
= 3*3*5*5
The 2 squares you can tile are one with a side length of 3 tiles and the other with a side length of 5 tiles.
.
Ed
Question 281121: Find the probability of answering the two multiple choice questions correctly if random guesses are made. Assume the questions each have five choices for the answer. Only one of the choices is correct.
Answer by edjones(4080) (Show Source):
Question 281097: A Researcher would like to test the effectiveness of a newly developed growth hormone. The Researcher knows that under normal circumstances laboratory rats reach an average weight of μ = 950 Grams at 10 Weeks of age. The Distribution of weights is normal with σ = 30. A random sample of n = 25 Newborn rats is obtained, and the hormone is given to each rat. When The rats in the sample reach 10 Weeks old, each rat is weighed. The Mean weight for this sample is M = 974.
a. Identify the independent and the dependent variables for this study.
b. Assuming a two-‐tailed test, state the null hypothesis in a sentence that includes the independent variable and the dependent variable.
c. Using symbols, state the hypotheses (H0 And H1) For the two tailed test.
d. Sketch the appropriate distributions, and locate the critical region for α =.05.
e. Calculate the test statistic (z-‐score) For the sample.
f. What decision should be made about the null hypothesis, and what decision should be made about the effect of the hormone?
Answer by stanbon(29602) (Show Source):
You can put this solution on YOUR website!A Researcher would like to test the effectiveness of a newly developed growth hormone.
The Researcher knows that under normal circumstances laboratory rats reach an average weight of μ = 950 Grams at 10 Weeks of age.
The Distribution of weights is normal with σ = 30.
A random sample of n = 25 Newborn rats is obtained, and the hormone is given to each rat.
When The rats in the sample reach 10 Weeks old, each rat is weighed. The Mean weight for this sample is M = 974.
------------------------------------------
a. Identify the independent and the dependent variables for this study.
Independent: amt of hormone
dependent: weight of the rats
------------------------------------------
b. Assuming a two-‐tailed test, state the null hypothesis in a sentence that includes the independent variable and the dependent variable.
Hormones do or do not make a difference in rat weights.
-------------------------------
c. Using symbols, state the hypotheses (H0 And H1) For the two tailed test.
Ho: u(no hor)-u(hor) = 0
Ha: u(no hor)-u(hor) is not equal to 0
-------------------------------
d. Sketch the appropriate distributions, and locate the critical region for α =.05.
+-invT(0.975 with df=24) = +-2.0639
-------------------------------
e. Calculate the test statistic (z-score) For the sample.
t(950-974)= -24/(standard deviation)
Note: No standard deviation for the sample was posted.
-------------------------------
f. What decision should be made about the null hypothesis, and what decision should be made about the effect of the hormone?
Note: No decision because test statistic cannot be calculated.
=====================================
Cheers,
Stan H.
Question 281118: Eleven people are entered in a race. If there are no ties, in how many ways can the first two places come out?
Answer by richwmiller(3756) (Show Source):
You can put this solution on YOUR website!There are 11 ways for first place
now there are 10 people left so there are 10 ways for second form each of those 11
11*10=110 ways for 1st and 2nd
Question 281088: Simplify:
(x2 + 4x - 5) / (x2 - 25/3x -15)
x2 is x squared
Answer by richwmiller(3756) (Show Source):
You can put this solution on YOUR website!The only probability involved is the probability that a tutor will answer your miscategorized question. Don't submit the same problem more than once.
x^2 is x squared
(x^2 + 4x - 5) / (x^2 - 25)/(3x -15)
(x^2 + 4x - 5) can be factored (x-1)*(x+5)
(x^2 - 25) can be factored ((x-5)(x+5)
(3x -15) can be factored 3*(x-5)
(x-1)*(x+5) divided by ((x-5)(x+5)) divided by (3(x-5))
(x+5) cancels out
(x-5) cancels out
leaving us with (x-1)/3
be generous with parentheses; they are free today
Question 281078: About 70% of the students at Fairview Technical College favor a new policy regarding parking on campus. Suppose we are interested in the proportion of 50 students in a matt class who favor the poilcy.
What is the probability that the proportion of the class who favor the poilcy is one-half or more?
What is the probability that the proportion of the class who favor the policy is between 60% and 80%?
What is the probability that the proportion of the class who favor the policy is less than 60%?
Answer by stanbon(29602) (Show Source):
You can put this solution on YOUR website!About 70% of the students at Fairview Technical College favor a new policy regarding parking on campus. Suppose we are interested in the proportion of 50 students in a matt class who favor the poilcy.
---
Sketch a Normal curve with "p" as the label of the horizontal axis.
Put 0.7 on a middle-point of the axis.
Put sqrt(0.7*0.3/50) = 0.0648 under 0.7 so you remember the standard deviation.
------------------------------------------
What is the probability that the proportion of the class who favor the policy is one-half or more?
z(0.5) = (0.5-0.7)/0.0648 = -3.0864
P(phat >=0.5)= P(z > -3.0864) = 0.9990
---------------------------------------------------
What is the probability that the proportion of the class who favor the policy is between 60% and 80%?
---
z(0.6) = (0.6-0.7)/0.0648 = -1.5432
z(0.8) = 1.5432
P(0.6 < phat <0.8) = P(-1.5432 < z < 1.5432) = 0.8772
---------------------------------------------------------
What is the probability that the proportion of the class who favor the policy is less than 60%?
Can you handle this now?
=============================
Cheers,
Stan H.
Question 281046: If you have 3 salads, 5 main dishes and 4 desserts, how many different meals can be made.
Answer by richwmiller(3756) (Show Source):
Question 281001: Runners from a particular country entered the new york marathon each year for the last 5 years and placed in the top 3. the probability of placing in the top 3 next year is?
Answer by brucewill(28) (Show Source):
You can put this solution on YOUR website!Insufficient information. We would need to know how many people run in the marathon, and we would need to know how many from the target country were entered.
Question 281005: a school sent 5 students to a spelling bee. the team was made up of 4 people. how many different teams of 4 students could be sent?
Answer by brucewill(28) (Show Source):
| 