Statistics and Probability Answers

The mean height of 50 Male students who showed above average participation in college athletics was 68.2 inches with a sd of 2.5 inches, while 50 students who showed no interest in such participation had a mean height of 67.5 inches with a standard deviation of 2.8 inches. Test the significance that male students who participate in college athletics are taller than the other male students
Hypothesis
Ho : Mu 1 <= Mu 2
H1 : Mu 1 > Mu 2

A recent survey of Financial Post (FP) readers reported that 40% of their subscribers regularly read the Wall Street Journal (WSJ), 32% read Time (T), and 11% read both the WSJ and T. What is the probability that a randomly selected reader reads WSJ or T or both?

Let Z have a standard normal N(0,1) distribution.
(a) Given zα defined by P(Z < zα) = α; find z0.879.
(b) Calculate the value of k such that P(−1.61 < Z < k) = 0.8958.

1.if given P(A intersect B) what is P(A intersect B')

Find the probability that the sum is as stated when a pair of dice is rolled odd OR less than 5

Hence, determine the probability of of a result with one die showing a 4 and the other a 5

Q4 Computer Action Company sells computers and computer parts by mail. The company assures its customers that products are mailed as soon as possible after an order is placed with the company. A sample of 50 recent orders showed that the mean time taken to mail products for these orders was 70 hours and the standard deviation was 16 hours. Construct 90% confidence interval for the mean time taken to mail products for all orders received at the office of this company.
Q5 A random sample of prices (in RM) for the 1GB thumbdrives sold in a mall is as follows.
15 30 45 18 21 29 25 43 33 27 35 20
Contruct a 99% confidence interval for the true population mean.
Q6 Fourteen eggs were randomly selected from a farm and the mass (in gram) is recorded as below.
X2 = 19779 X = 487
Construct a 95% confidence interval for the mean mass of eggs.

Q3 60 smokers were questioned about the number of hours they sleep each day. We want to test the hypothesis that the smokers need less sleep than the general public which needs an average of 8 hours of sleep. If the sample mean is 7.5 and known population standard deviation is 0.2, what can you conclude using significance level of 0.01.

TUTORIAL CHAPTER HYPOTHESIS TEST
Q1 An editor of a publishing company claims that the mean time taken to write a textbook is more than 35 months. A sample of 40 textbook’s authors were selected and found that the mean time taken to write the textbooks was 32 months with a standard deviation of 16 months. Assuming that the time taken to write a textbook is normally distributed, test 5% significant level, is the editor’s claim true?
Q2 The amount of juice extracted from each pineapple is normally distributed with a standard deviation of 3 gram. A random sample of 15 pineapples has a mean amount of juice of 100 gram. Is there evidence to support the claim that the juice of pineapple is more than 120 gram? Use a = 0.05.