Tutors Answer Your Questions about Probability-and-statistics (FREE)
Question 89211: I need help with 2/3 three problems:
1) Find the probability of the result using the normal curve approximation to the binomial distribution. On a hospital floor, 60 patients have a disease with a mortality rate of 0.1. Five of them die.
2) Find the probability fo the result using the normal curve approximation to the binomial distribution. A battery company has found that the defective rate of its batteries is 0.03. Each day, 400 batteries are randomly tested. On Tuesday, 14 are found to be defective.
Click here to see answer by stanbon(57214)  |
Question 89327: I need to find the classic probability of rolling a 1 (or any number) out of 8 dice. I'm not looking for the total face value, just the frequency of rolling a 1 out of 8 dice. So, "What is the probability that you will roll a single 1 out of 8 dice?", "What is the probability you will roll two 1s out of 8 dice?" and so on.
What I have tried:
(when rolling no 1s out of 8 dice) I used: 
(when rolling a single 1 out of 8 dice) I used:  .
(when rolling two 1s out of 8 dice) I used: 
Alternately, I tried the same thing without using powers in my formulas.... but this didn't seem to help.
My total probability for the set did not add up to 1, so I think I must be missing a step? Please help!
Click here to see answer by stanbon(57214) |
Question 89212: Here is the 3/3 question i need hlep on.
Provide an appropirate responce.
A) Describe some situations wher ethe mode is the best average to use to describe data.
B) A test can have grades from 0 to 100, inclusive. If 17 students take the test, is the median necessarily 50? Explain show work if possible
C) The set of grades from different classes is recorded. In the first class, the mean is 80 and the standard deviation is 2. In the second class, thte mean is 70 and the standard deviation is 5. IN the third class, the mean is 72 and the standard deviation is 4. In which class does it appear that a student is most likely to recieve a grade of 90 or higher?
D) Give a normal distribution, is it more likely that a value is within one standard deviation above the mean or within one standard deviation below the mean? or are both equally likely?
Click here to see answer by stanbon(57214) |
Question 89502: I need help with these problems please explain them to me step by step thanks....I have an exam tomorrow i want to really understand them;.....
Problem #1
Find the percent of the total area under a normal curve that is contained within the specified interval. Between the mean and 1.64 standard deviations from the mean
Problem #2
Find the percent of the total area under the standard normal curve between the given z-scores.
z= -1.10 and z = -0.36
Click here to see answer by stanbon(57214) |
Question 89947: how many five-poker hands consisting of the following distribution are there?
a- aflush ( all five cards of a signle suit)
b- theree of kind (three aces and two other cards)
c- two pairs ( two aces, two kings and one other card)
d- A straight ( all five cards in a sequence)
Click here to see answer by stanbon(57214) |
Question 90119: A statistics department within a university changed its curriculum degree requirements. One of the professors within the department expressed concern that this change would result in lower statistical skills among students. Students in the program before the change took place demonstrated a mean of 70 points on statistics proficiency exam. Thirty-six students in the new program took the proficiency exam and had the following scores:
68 68 78 61 58 72
62 65 53 57 52 76
66 54 58 81 76 78
75 81 88 48 76 59
61 80 78 67 80 58
77 56 70 66 72 79
Do the data (mean = 68.16, standard deviation = 10.25) indicate that the new curriculum degree requirements lower statistical proficiency exam scores? Use the 5% level of significance.
Click here to see answer by stanbon(57214) |
Question 90210: A multiple choise test has 3 questions, the first question has 3 possible answers a, b, and c the second question has 4 possible answers a b c and d the 3rd question has 5 possible answers a b c d and e. A student completely does not understand any question and just randomly picks an answer for each question.
A) how many possible choices can he answer with
B) Find the probability that the student answers all 3 questions correctly
C) Find the probability that the studnet answers correctly 1 question and gets the other two questions incorrect.
Click here to see answer by stanbon(57214) |
Question 90209: Five cards are dealt at random from a standard deck (of 52 cards). Find the probability that the five card poker hand contains the following cards\
I know the possible outcomes are 2598960
a. 2 kings 2 queens and 1 jack
b. 3 aces 1 king and 1 queen
c. 1 ace 1 king 1 queen and 1 jack
d. 2 diamonds and 3 hearts
Click here to see answer by stanbon(57214) |
Question 89946: how many five-poker hands consisting of the following distribution are there?
a- aflush ( all five cards of a signle suit)
b- theree of kind (three aces and two other cards)
c- two pairs ( two aces, two kings and one other card)
d- A straight ( all five cards in a sequence)
Click here to see answer by stanbon(57214) |
Question 90821: Please help me solve the following:
There are 9 ways to get from Point A to Point B. There are 8 ways to get from Point B to Point C. How many ways can you get from Point A to Point B to Point C and back to Point A without retracing your steps? I have tried online tutoring, 9! 9!+8!, counting (which takes forever) and numerous websites. I cannot find a problem similar to this one.
Thank you
Click here to see answer by kev82(148) |
Question 90848: Here is a question that someone asked you and you have already answered it. I do not understand how to input your solution into the calculator.
ORIGINAL QUESTION: Find the percent of the total area under a normal curve that is contained within the specified interval. Between the mean and 1.64 standard deviations from the mean
YOUR ANSWER: Find the percent of the total area under a normal curve that is contained within the specified interval. Between the mean and 1.64 standard deviations from the
You need a z-chart or a calculator with z capability, like a TI 83 or 84
On the z cart find z=1.64. The chart tells you the area over the interval
[0,1.64] = 0.9495-0.5000 = 0.4495
My QUESTION: I do not understand the z capability that you are talking about. I have a TI-83. I looked all in the manual and I cannot find anything about z charts. Can you help?
Click here to see answer by stanbon(57214) |
Question 90905: House Edge in Blackjack: In a large casino, thehouse wins on its blackjack tables with a probablility of 50.7%. All bets at blackjack are 1 to 1: If you win, you gain the amount you bet; If you lose, you lose the amount you bet.
a: What is the expected value to you of a single game? What is the house edge? If I am able to understand part a I should be able to understand the the rest of the problem. 3 days to go until the quarter is over. Thanks very much for your help this past year.
Click here to see answer by stanbon(57214) |
Question 91194: From 9 mathematicians and 6 physicists a committee of 4 mathematicians and 3 physicists is to be formed.What is the probability that commitee has
a) 3 particular mathematicians b)one particular physicist
Click here to see answer by stanbon(57214) |
Question 91436: The following puzzler was given on the Car Talk radio program on February 19, 2001.*
“Three different numbers are chosen at random, and one is written on each of three slips of paper. The slips are then placed face down on the table. The objective is to choose the slip upon which is written the largest number. Here are the rules: You can turn over any slip of paper and look at the amount written on it. If for any reason you think this is the largest, you’re done; you keep it. Otherwise you discard it and turn over a second slip. Again, if you think this is the one with the biggest number, you keep that one and the game is over. If you don’t, you discard that one too. . . . The chance of getting the highest number is one in three. Or is it? Is there a strategy by
which you can improve the odds?”
The answer to the puzzler is that you can indeed improve the probability of getting the highest number by the following strategy. Pick one of the slips of paper, and after looking at the number, throw it away. Then pick a second slip; if it has a larger number than the first slip, stop. If not, pick the third slip. Find the probability of winning with this strategy.
Thank you so much!
Click here to see answer by bucky(2189) |
Question 91640: Can someone please help me with these questions I am really stuck.
In questions 1-6, the universal ser E = {a,b,c,d,e,f,g,h}, and A = {a,e}
1. Find A n (B U C)
2. Find A^C (B n C^c)
3. Find (A U B)^c n B
4. Find cartesian product A X B
5. Find cartesian product B X A
6. Find cartesian product A X C^c
7. You toss three a fair coin three times. What i the probability of getting at least two heads.
8. You toss a fair coin three times. What is the probability of getting three tails.
9. You roll three fair dice. What is the probability of getting a sum equal to 10.
10. You randomly pich four cards from a deck of 52. What is the probability of getting four kings.
Thanks so much in advance for your help.
Click here to see answer by stanbon(57214) |
Question 91555: The following hypotheses are given.
H0pie=0
H1pie does not =1
A sample of 120 observations revealed that p = .30. At the .05 significance level, can the null hypothesis be rejected?
State the decision rule.
Compute the value of the test statistic.
What is your decision regarding the null hypothesis?
Note: It is recommended that you use the five-step hypothesis-testing procedure in solving the following problems.
Click here to see answer by stanbon(57214) |
Question 91552: Dr. Patton is a Professor of English. Recently he counted the number of misspelled words in a group of student essays. For his class of 40 students, the mean number of misspelled words was 6.05 and the standard deviation 2.44 per essay. Construct a 95 percent confidence interval for the mean number of misspelled words in the population of student essays.
Click here to see answer by stanbon(57214) |
Question 91551: According to an IRS study, it takes an average of 330 minutes for taxpayers to prepare, copy, and electronically file a 1040 tax form. A consumer watchdog agency selects a random sample of 40 taxpayers and finds the standard deviation of the time to prepare, copy, and electronically file form 1040 is 80 minutes.
What assumption or assumptions do you need to make about the shape of the population?
What is the standard error of the mean in this example?
What is the likelihood the sample mean is greater than 320 minutes?
What is the likelihood the sample mean is between 320 and 350 minutes?
What is the likelihood the sample mean is greater than 350 minutes?
Click here to see answer by stanbon(57214) |
Question 91549: A manufacturer of window frames knows from long experience that 5 percent of the production will have some type of minor defect that will require an adjustment. What is the probability that in a sample of 20 window frames:
None will need adjustment?
At least one will need adjustment?
More than two will need adjustment?
Thank you so much to a of the tutors, I can spens hours to get nowhere, I coud use some guidance.
Thanks
Click here to see answer by stanbon(57214) |
Question 90733: A box contains one yellow , two red, and three green balls. Two
balls are randomly chosen without replacement. Define the following
events:
A:{one of the balls is yellow}
B:{at least one ball is red}
C:{both balls are green}
D{both balls are the same color}
i`m not sure how to start this really usually i make a list
or tree or venn diagram , or can just look and eliminate
to do these , usually the problems will have numbers or i have
to fill in the diagram, but none have had balls and colors
i`m not sure if i need to use the probability like 1/6 for the
yellow ball and try and figure it out or even if the sample
set will be all the balls or will be different on each one.
The formulas we have been using are like
P(A|B)=P(A u B)/ P(B)
P (A u B)= P(A)x P(A|B)
P (A n B)= P(A) x P(B)
P (A|B)= P(A)
P (B|A)= P (B)
etc.
Click here to see answer by stanbon(57214) |
Question 90734: A box contains one yellow , two red, and three green balls. Two
balls are randomly chosen without replacement. Define the following
events:
A:{one of the balls is yellow}
B:{at least one ball is red}
C:{both balls are green}
D{both balls are the same color}
P(B|A')=
P(D|B')=
P(C|A)=0
P(A'|B)=
P(B'|D)=
P(D|C)=
i knew one anyway *s*
i`m not sure how to start this really usually i make a list
or tree or venn diagram , or can just look and eliminate
to do these , usually the problems will have numbers or i have
to fill in the diagram, but none have had balls and colors
i`m not sure if i need to use the probability like 1/6 for the
yellow ball and try and figure it out or even if the sample
set will be all the balls or will be different on each one.
The formulas we have been using are like
P(A|B)=P(A u B)/ P(B)
P (A u B)= P(A)x P(A|B)
P (A n B)= P(A) x P(B)
P (A|B)= P(A)
P (B|A)= P (B)
etc.
Click here to see answer by stanbon(57214) |
Question 92064: Six basic colors are to be used in decorating a new condominium. They are to be applied to a unit in groups of four colors. One unit might have gold as the principal color, blue as a complementary color, red as the acent color and touches of white. Another unit might have blue as the principal color, white as the complimentary color, gold as the accent color and touches of red. If repetitions are permitted, how many different units can be decorated?
a) 7825
b) 25
c) 125
d) 1296
Click here to see answer by stanbon(57214) |
Question 92307: a football coach needs 12 players to ride a float in a parade. he randomly selects names from a helmet. the helmet contains the names of 4 freshmen, 13 sophmores, 14 juniors, and 8 seniors. what is the probability the first two names chosen are juniors?
Click here to see answer by checkley71(8403) |
Question 92277: The probability that Andy studies math over break is 0.3 and the probability that Betty independently studies over break is 0.4. Find the probability Andy studies math over break and Betty doesn't.
Click here to see answer by Nate(3500) |
Question 92338: A simple random sample is to be drawn from a population of 1200, in order to have 90%confidence that the sampling error in estimating "n"is no more the 0.03, what sample size will be necessary?
P.S. I just ca not get this one and I have tryed.
Click here to see answer by stanbon(57214) |
Question 92278: One urn contains 3 read and 7 white marbles. A second urn contains 2 red and 8 white marbles. One urn is selected and a ball drawn. The probability of selecting the first urn is 0.4 and the probability of selecting the second is 0.6. If a white ball is drawn, find the probability it came from the second urn.
Click here to see answer by stanbon(57214) |
Question 92605: 930-μ = 1.2816
______
100
I am having a brain cramp and cannot remember how to solve for μ in this problem. I have the answer from my worksheet (801.8448) but cannot remember how to do the work!!
Thank you
Click here to see answer by psbhowmick(529)  |
Question 93734: A single card is drawn from an ordinary deck of cards. Find the indicated probabilities if the given information is known about the chosen card.
a. P (club/not a diamond)
b. P (face card/king)
A player rolls a single die. If an even number comes up, he wns that number of dollars. If an odd number comes up he loses that number of dollars. What is the expected value (mathematical expectation) of this game?
Click here to see answer by stanbon(57214) |
Question 93999: A secretary periodically checks to see how many of the 3 lines into the office are busy. Her findings for one week were the following:
No Lines Busy/ Frequency
0/ 20
1/ 65
2/ 25
3/ 10
Let the random variable X be the number of lines busy. Find the probability distribution of X.
Click here to see answer by Edwin McCravy(8879)  |
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Older solutions: 1..45, 46..90, 91..135, 136..180, 181..225, 226..270, 271..315, 316..360, 361..405, 406..450, 451..495, 496..540, 541..585, 586..630, 631..675, 676..720, 721..765, 766..810, 811..855, 856..900, 901..945, 946..990, 991..1035, 1036..1080, 1081..1125, 1126..1170, 1171..1215, 1216..1260, 1261..1305, 1306..1350, 1351..1395, 1396..1440, 1441..1485, 1486..1530, 1531..1575, 1576..1620, 1621..1665, 1666..1710, 1711..1755, 1756..1800, 1801..1845, 1846..1890, 1891..1935, 1936..1980, 1981..2025, 2026..2070, 2071..2115, 2116..2160, 2161..2205, 2206..2250, 2251..2295, 2296..2340, 2341..2385, 2386..2430, 2431..2475, 2476..2520, 2521..2565, 2566..2610, 2611..2655, 2656..2700, 2701..2745, 2746..2790, 2791..2835, 2836..2880, 2881..2925, 2926..2970, 2971..3015, 3016..3060, 3061..3105, 3106..3150, 3151..3195, 3196..3240, 3241..3285, 3286..3330, 3331..3375, 3376..3420, 3421..3465, 3466..3510, 3511..3555, 3556..3600, 3601..3645, 3646..3690, 3691..3735, 3736..3780, 3781..3825, 3826..3870, 3871..3915, 3916..3960, 3961..4005, 4006..4050, 4051..4095, 4096..4140, 4141..4185, 4186..4230, 4231..4275, 4276..4320, 4321..4365, 4366..4410, 4411..4455, 4456..4500, 4501..4545, 4546..4590, 4591..4635, 4636..4680, 4681..4725, 4726..4770, 4771..4815, 4816..4860, 4861..4905, 4906..4950, 4951..4995, 4996..5040, 5041..5085, 5086..5130, 5131..5175, 5176..5220, 5221..5265, 5266..5310, 5311..5355, 5356..5400, 5401..5445, 5446..5490, 5491..5535, 5536..5580, 5581..5625, 5626..5670, 5671..5715, 5716..5760, 5761..5805, 5806..5850, 5851..5895, 5896..5940, 5941..5985, 5986..6030, 6031..6075, 6076..6120, 6121..6165, 6166..6210, 6211..6255, 6256..6300, 6301..6345, 6346..6390, 6391..6435, 6436..6480, 6481..6525, 6526..6570, 6571..6615, 6616..6660, 6661..6705, 6706..6750, 6751..6795, 6796..6840, 6841..6885, 6886..6930, 6931..6975, 6976..7020, 7021..7065, 7066..7110, 7111..7155, 7156..7200, 7201..7245, 7246..7290, 7291..7335, 7336..7380, 7381..7425, 7426..7470, 7471..7515, 7516..7560, 7561..7605, 7606..7650, 7651..7695, 7696..7740, 7741..7785, 7786..7830, 7831..7875, 7876..7920, 7921..7965, 7966..8010, 8011..8055, 8056..8100, 8101..8145, 8146..8190, 8191..8235, 8236..8280, 8281..8325, 8326..8370, 8371..8415, 8416..8460, 8461..8505, 8506..8550, 8551..8595, 8596..8640, 8641..8685, 8686..8730, 8731..8775, 8776..8820, 8821..8865, 8866..8910, 8911..8955, 8956..9000, 9001..9045, 9046..9090, 9091..9135, 9136..9180, 9181..9225, 9226..9270, 9271..9315, 9316..9360, 9361..9405, 9406..9450, 9451..9495, 9496..9540, 9541..9585, 9586..9630, 9631..9675, 9676..9720, 9721..9765, 9766..9810, 9811..9855, 9856..9900, 9901..9945, 9946..9990, 9991..10035, 10036..10080, 10081..10125, 10126..10170, 10171..10215, 10216..10260, 10261..10305, 10306..10350, 10351..10395, 10396..10440, 10441..10485, 10486..10530, 10531..10575, 10576..10620, 10621..10665, 10666..10710, 10711..10755, 10756..10800, 10801..10845, 10846..10890, 10891..10935, 10936..10980, 10981..11025, 11026..11070, 11071..11115, 11116..11160, 11161..11205, 11206..11250, 11251..11295, 11296..11340, 11341..11385, 11386..11430, 11431..11475, 11476..11520, 11521..11565, 11566..11610, 11611..11655, 11656..11700, 11701..11745, 11746..11790, 11791..11835, 11836..11880, 11881..11925, 11926..11970, 11971..12015, 12016..12060, 12061..12105, 12106..12150, 12151..12195, 12196..12240, 12241..12285, 12286..12330, 12331..12375, 12376..12420, 12421..12465, 12466..12510, 12511..12555, 12556..12600, 12601..12645, 12646..12690, 12691..12735, 12736..12780, 12781..12825, 12826..12870, 12871..12915, 12916..12960, 12961..13005, 13006..13050, 13051..13095, 13096..13140, 13141..13185, 13186..13230, 13231..13275, 13276..13320, 13321..13365, 13366..13410, 13411..13455, 13456..13500, 13501..13545, 13546..13590, 13591..13635, 13636..13680, 13681..13725, 13726..13770, 13771..13815, 13816..13860, 13861..13905, 13906..13950, 13951..13995, 13996..14040, 14041..14085, 14086..14130, 14131..14175, 14176..14220, 14221..14265, 14266..14310, 14311..14355, 14356..14400, 14401..14445, 14446..14490, 14491..14535, 14536..14580, 14581..14625, 14626..14670, 14671..14715, 14716..14760, 14761..14805, 14806..14850, 14851..14895, 14896..14940, 14941..14985, 14986..15030, 15031..15075, 15076..15120, 15121..15165, 15166..15210, 15211..15255, 15256..15300, 15301..15345, 15346..15390, 15391..15435, 15436..15480, 15481..15525, 15526..15570, 15571..15615, 15616..15660, 15661..15705, 15706..15750, 15751..15795, 15796..15840, 15841..15885, 15886..15930, 15931..15975, 15976..16020, 16021..16065, 16066..16110, 16111..16155, 16156..16200, 16201..16245, 16246..16290, 16291..16335, 16336..16380, 16381..16425, 16426..16470, 16471..16515, 16516..16560, 16561..16605, 16606..16650, 16651..16695, 16696..16740, 16741..16785, 16786..16830, 16831..16875, 16876..16920, 16921..16965, 16966..17010, 17011..17055, 17056..17100, 17101..17145, 17146..17190, 17191..17235, 17236..17280, 17281..17325, 17326..17370, 17371..17415, 17416..17460, 17461..17505, 17506..17550, 17551..17595, 17596..17640, 17641..17685, 17686..17730, 17731..17775, 17776..17820, 17821..17865, 17866..17910, 17911..17955, 17956..18000, 18001..18045, 18046..18090, 18091..18135, 18136..18180, 18181..18225, 18226..18270, 18271..18315, 18316..18360, 18361..18405, 18406..18450, 18451..18495, 18496..18540, 18541..18585, 18586..18630, 18631..18675, 18676..18720, 18721..18765, 18766..18810, 18811..18855, 18856..18900, 18901..18945, 18946..18990, 18991..19035, 19036..19080, 19081..19125, 19126..19170, 19171..19215, 19216..19260, 19261..19305, 19306..19350, 19351..19395, 19396..19440, 19441..19485, 19486..19530, 19531..19575, 19576..19620, 19621..19665, 19666..19710, 19711..19755, 19756..19800, 19801..19845, 19846..19890, 19891..19935, 19936..19980, 19981..20025, 20026..20070, 20071..20115, 20116..20160, 20161..20205, 20206..20250, 20251..20295, 20296..20340, 20341..20385, 20386..20430, 20431..20475, 20476..20520, 20521..20565, 20566..20610, 20611..20655, 20656..20700, 20701..20745, 20746..20790, 20791..20835, 20836..20880, 20881..20925, 20926..20970, 20971..21015, 21016..21060, 21061..21105, 21106..21150, 21151..21195
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