Questions on Algebra: Probability and statistics answered by real tutors!

Tutors Answer Your Questions about Probability-and-statistics (FREE)

Question 475211: . A Math test has a mean of 36 and standard deviation of 11.0. Find the corresponding z scores for:

I. a test score of 8
II. a test score of 53
Thank you

Click here to see answer by robertb(4012)

Question 475273: Let X be normally distributed random variable with u = 100 and standard deviation = 10. the probability that X is between 70 and 110 is (to the nearest whole percent)
Click here to see answer by robertb(4012)

Question 474993: "A box contains 13 orange blocks, 19 yellow blocks, and 8 purple blocks. Paul randomly chose a block, then he randomly chose another block without replacing the first block.

What is the probability that he chose 2 orange blocks? Write your answer as a decimal."
Click here to see answer by robertb(4012)

Question 474914: Four married couples have brought 8 seats in a row for a concert. In how many different ways can they be seated
a. with no restrictions?
b. if each couple is to sit together?
c. if all men sit together to the right of all women?
Click here to see answer by robertb(4012)

Question 475154: What is the ratio of the surface areas for a pair of similar cylinders when the ratio of the heights 3:1?
Click here to see answer by richard1234(5390)

Question 475311: a restaurant offers 6 appetisers, 8 entrées, 4 desserts, and 3 beverage options. if you order only one item from each of the categories, how many different meal combinations would there be?
Click here to see answer by josmiceli(9664)

Question 474840: Find the percentage of area under a normal curve between the mean and 0.1 standard deviations from the mean.
Click here to see answer by robertb(4012)

Question 474962: Using the data set below, please calculate the:
1 4 2.5 5 3
- Range
- What would be the percentile rank of the number 2.5?
Thank you
Click here to see answer by robertb(4012)

Question 475325: if a 3-digit number (000 to 999) i chosen at random, find the
probability that exactly 1 digit will be >5.
Click here to see answer by robertb(4012)

Question 475334: Determine if the argument is valid or invalid. Give a reason to justify answer.
If the bell rings, then we answer the door.
The bell rings.
We answer the door.
O Valid by the law of detachment
O Valid by the law of contraposition
O Invalid by fallacy of the converse
O Invalid by fallacy of the inverse
O Valid by the law of syllogism
O Valid by disjunctive syllogism
Click here to see answer by Theo(3458)

Question 15704: Hi,
I'm trying to solve this problem: If a 3-digit number (000 to 999) is chosen at random, find the probability that exactly one digit will be less than 2.
I got to the point of (1/10)^2 * 2/10 but I'm not sure or am I answering another problem. Please help asap.
Click here to see answer by biplavmehta(3)

Question 15532: I submitted this problem Friday evening and I got no response. I need to know if I'm right or wrong, it's due tomorrow.
If 10 cards are drawn without replacement from an ordinary deck, find the probability of obtaining exactly 3 aces or exactly 3 kings (or both). I tried
using (52 choose 10) for the denominator and (10 choose 3)^4 for the numerator(4 for each suite). It seems as though I'm missing something. Please help asap.

Click here to see answer by biplavmehta(3)

Question 15121: If a couple plans to have eight children, find the probability that they are all of the same gender.
Thanks a lot.
Click here to see answer by biplavmehta(3)

Question 475363: Construct a truth table for (p Λ ~ q) ↔ q
Click here to see answer by Theo(3458)

Question 475442: Suppose you have 50 diffrent numbers that you play in a lottery every time they draw and the odds of winning are 1 in 5,138,133 whats the odds of one of my numbers winning/
Click here to see answer by Alan3354(30993)

Question 475441: two digits are randomly selected without repition; compute the probability that their sum is is odd
Click here to see answer by Edwin McCravy(8893)

Question 475492: Consider a binomial experiment with 20 trials and probability 0.45 on a single trial. Use an approximation to the normal distribution to find the probability of exactly 10 successes. Round your answer to the thousandths place. (Remember this means you will need to find the endpoints and then find a z-score for each and subtract the two areas).
Click here to see answer by stanbon(57282)

Question 420219: Determine the sampling error of 10 randomly selected students from a class of 125 students has a mean of 2.8. Assume the grade point averages of 125 students has a mean of 3.5.
A= 0.7 B= 3.15 C= -0.7 D= 2.45
Click here to see answer by litty1(1)

Question 475482: Jason has two bags of letters. One of the bags contains each of the six letters in the word ELEVEN, and the other contains the six letters in the word TWELVE, but he cannot remember which bag contains which letters. After drawing four letters from one bag, what is the probability that Jason still won’t be able to determine which bag contains which letters?
Click here to see answer by Edwin McCravy(8893)

Question 475455: Two digits are randomly selected without repetition, compute probability tha their sm is odd... also that their product is odd
Click here to see answer by Edwin McCravy(8893)

Question 475573: 40(0.6)+30(0.4)-3
find the mean
Click here to see answer by edjones(7569)

Question 475616: You have measured the percentage of days your company met production targets across two sites. At one site, you measure 80 days and found that the site missed the production goals 11 times. At site two, you measured 92 days and found that the site missed the production goals 10 times. At the 90% confidence level, can you say that site two missed the production goal fewer times than site one? State your hypothesis:

Click here to see answer by stanbon(57282)

Question 474805: Given that P(A) = 0.3 and P(b) = 0.5, and P(A and B) = 0.12, determine P(B/A)
Click here to see answer by robertb(4012)

Question 475415: This is a probability question!
There is a graph, and the numbers on the bottom range from 0 to 2.7, with a line steadily moving from 0 to 1, increasing to 2 and then decreasing to 2.7. The question is, What is P(.5
Click here to see answer by richard1234(5390)

Question 475702: At a golf tournament 10 golfers , 6 of them are girls 2 of the girls are over 40 , 3 of the men are over 40 .
What is the probability that the winner is a girl or over 40 ?
Click here to see answer by ewatrrr(10682)

Question 475780: You have 100 total envelopes. 25 envelopes have the letter "L", 25 have the letter "I", 25 have the letter "F" and 25 have the letter "E". How many draws will it take before you spell the word "life"?

Click here to see answer by richard1234(5390)

Question 475850: 1.What price do farmers get for the peach crops? in the third week of June, a random sample of 40 farming regions gave a sample mean of $6.88 per basket. assume that the standard deviation is known to be $1.92 per basket. find a 90% confidence interval for the population mean price per basket that farmers in this region get for their peach crop.
2.Using the the information from #1, calculate the margin of error. Round your answer to 2 decimal places
Click here to see answer by stanbon(57282)

Question 475902: .Consider college officials in admissions registration, counseling, financial aid campus ministry, food services, and so on. How much money do these people make each year? Suppose you read in your local newspaper that 45 officials in student services earn an average of $50,340 each year. Assume that the standard deviation is $10,780 for salaries of college officials and student services. Find a 90% confidence interval for the population mean salaries of such personnel. Round your answer to the nearest dollar and don;t forget to use the $ sign.
2.What is the margin of error for problem 1? Round your answer to the nearest dollar and don;t forget to use the $ sign.

Click here to see answer by stanbon(57282)

Question 475911: Same computed a 90% confidence interval for U (mean of population) from a specific random sample of size n. He claims that at the 90% confidence level, his confidence interval contains U(mean of population). Is this claim correct. Explain.

Click here to see answer by stanbon(57282)

Question 475894: I need help with the test statistic in problem 10.8 ? Top food consumed by adults
Click here to see answer by stanbon(57282)

Question 475934: An exam has ten true-false questions. A student who has
not studied answers all ten questions by just guessing. Find
the probability that the student correctly answers the given
number of questions.
(a) All ten questions
(b) Exactly seven questions
thankyou! :)
Click here to see answer by jim_thompson5910(28536)

Question 475972: A box contains 5 brown and 4 white socks. A man takes out two socks. The probability that they are of the same color is:
Click here to see answer by stanbon(57282)

Question 475972: A box contains 5 brown and 4 white socks. A man takes out two socks. The probability that they are of the same color is:
Click here to see answer by Edwin McCravy(8893)

Question 475963: Hi, I'm wondering, what is least likely to happen:
to pick (randomly from a deck of 52)
all 7's in a deck of cards without replacement and no shuffling
all 7's in a deck without replacement but with shuffling
all 7's in a deck with replacement and with shuffling
or
to pick all 7's in a deck with replacement and without shuffling?
Which one is the least probable and what is the probability of such an event occurring? Thanks.
Click here to see answer by stanbon(57282)

Question 475940: 1.Use Table 4 of the appendix to find tc for a 0.95 confidence level when the sample size is 12.
-I got .540 but i do not think it is right.
2.Use Table 4 of the appendix to find tc for a 0.95 confidence level when the sample size is 18.
-I got .189 but i do not think it is right.
3.Use Table 4 of the appendix to find tc for a 0.99 confidence level when the sample size is 4.
- i got 4.604 and i know this answer is incorrect.
4.Use Table 4 of the appendix to find tc for a 0.90 confidence level when the sample size is 22.
-I got 1.717 and i know this answer is incorrect.
Click here to see answer by stanbon(57282)

Question 475938: From a group of 30 contestants, six are to be chosen as
semifinalists, then two of those are chosen as finalists, and
then the top prize is awarded to one of the finalists. In how
many ways can these choices be made in sequence?
thankyou! :)
Click here to see answer by stanbon(57282)

Question 476009: I'm having problems with this one any help would be appreciated
In a standard normal distribution, what z value corresponds to 17% of the data between the mean and the z value?
Click here to see answer by MathLover1(6625)

Question 476129: A card is selected from a standard deck of 52 playing cards.?
A standard deck of cards has 12 face cards and four Aces (Aces are not face cards). Find the probability of selecting
· a prime number under 10 given the card is red. (1 is not prime.)
· a King, given that the card is not a heart.
· a nine given the card is a face card.
Show step by step work. Give all solutions exactly in reduced fraction form.
Click here to see answer by stanbon(57282)

Question 476127: What is the probability that if you choose 13 cards out of a deck of cards, all cards will be spades?
I'm lost on how to solve this problem.
Click here to see answer by stanbon(57282)

Question 476132: What is an example of a negative consequence resulting from having committed a Type II error?
Click here to see answer by stanbon(57282)

Question 476132: What is an example of a negative consequence resulting from having committed a Type II error?
Click here to see answer by classof2012(1)

Question 476235: To determine the number of deer in a game reserve, a forest ranger catchers 127 deer, tags them and releases them. Later 189 deer are caught and it is found that 82 of them are tagged. Estimate how many deer are in the game reserve and round the answer to the nearest interger. I got 293 but I don't think it's right, please assist.
Click here to see answer by ccs2011(207)

Question 476293: In terms of the mean and standard deviation:
- What does it mean to say that a particular value of x has a standard score of +1.5?
- What does it mean to say that a particular value of x has a z-score of -2.6?

thank you kindly
Click here to see answer by stanbon(57282)

Question 476297: SAT I scores around the nation tend to have a mean scale score around 500, a standard deviation of about 100 points and are approximately normally distributed. A person who scores (a perfect) 800 on the SAT I has approximately what percentile rank within the population?
Thanks
Click here to see answer by stanbon(57282)

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