1. It has been estimated that 43% of the economics graduates believe that a course in History of Economic Thought is very important to provide a context for the understanding of modern economic theory. Find the probability that more than one-half of a random sample of 80 economics graduates have this belief. (Select the closest one)
Select one:
a. 0.1643
b. 0.0108
c. 0.3218
d. 0.9980
e. 0.1020
2. It has been reported that the average time to download the home page from a government website was 0.9 seconds. Suppose that the download times were normally distributed with a standard deviation of 0.3 seconds. If random samples of 36 download times are selected, what are the lower and upper values of the interval to include 80% of the sample means symmetrically distributed around the population mean? (Select the closest one)
Select one:
a. 0.678, 0.885
b. 0.836, 0.964
c. 0.173, 0.348
d. 0.457, 0.782
3. According to a hospital administrator, historical records over the past 10 years have shown that 20% of the major surgery patients are dissatisfied with after-surgery care in the hospital. A scientific poll based on 400 hospital patients has just been conducted.
What is the probability that less than 64 patients will not be satisfied with the after-surgery care? (Select the closest one)
Select one:
a. 4.56%
b. 47.72%
c. 2.28%
d. 97.72%
e. 95.44%
4. The internal auditing staff of a local manufacturing company performs a sample audit each quarter to estimate the proportion of accounts that are delinquent more than 90 days overdue. The historical records of the company show that over the past 8 years 14 percent of the accounts are delinquent. For this quarter, the auditing staff randomly selected 250 customer accounts. What are the mean and the standard deviation of the sampling distribution for the proportion? (Select the closest one)
Select one:
a. 35 and 30.1
b. 35 and 5.486
c. 0.14 and 0.1204
d. 14 and 250
e. 0.14 and 0.0219
5. If a population distribution is known to be normal, then it follows that:
Select one:
a. None of the above/below
b. The sample standard deviation must equal the population standard deviation
c. The sample mean must equal the population mean for large samples
d. All of the above/below
e. The sample mean must equal the population mean
6. The average score of all professional 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. (Select the closest one)
Select one:
a. 0.1587
b. More information is needed
c. 0.0228
d. 0.2514
e. 0.3707