# Statistics: Normal Distribution and Confidence Interval

1734 WordsJun 17, 20117 Pages
Study Set for Midterm II, Chapters 7 & 8 ESSAY. Write your answer in the space provided or on a separate sheet of paper. 1) The average score of all pro golfers for a particular course has a mean of 70 and a standard deviation of 3.0. Suppose 36 golfers played the course today. Find the probability that the average score of the 36 golfers exceeded 71. 2) At a computer manufacturing company, the actual size of computer chips is normally distributed with a mean of 1 centimeter and a standard deviation of 0.1 centimeter. A random sample of 12 computer chips is taken. What is the probability that the sample mean will be between 0.99 and 1.01 centimeters? MULTIPLE CHOICE. Choose the one alternative that best…show more content…
19) Referring to Table 7-7, the population mean of all possible sample proportions is ________. 19) _____________ 20) Referring to Table 7-7, the standard error of all possible sample proportions is ________. 20) _____________ 21) Referring to Table 7-7, ________% of the samples are likely to have between 35% and 40% who take advantage of online customer service. 21) _____________ MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 22) If you were constructing a 99% confidence interval of the population mean based on a sample of n=25 where the standard deviation of the sample s = 0.05, the critical value of t will be: 22) ______ A) 2.7874 B) 2.7969 C) 2.4851 D) 2.4922 23) A confidence interval was used to estimate the proportion of statistics students that are female. A random sample of 72 statistics students generated the following 90% confidence interval: (0.438, 0.642). Using the information above, what size sample would be necessary if we wanted to estimate the true proportion to within ±0.08 using 95% confidence? 23) ______ A) 150 B) 105 C) 420 D) 597 24) A major department store chain is interested in estimating the average amount its credit card customers spent on their first visit to the chain's new store in