Part -1:
1. In a study conducted by UCLA, it was found that 25% of college freshmen support increased military spending. If 6 college freshmen are randomly selected, find the probability that 3 or more support increased military spending
A. 0.8306
B. 0.1318
C. 0.1694
D.0 .9624
2. A fair die is rolled 10 times. What is the probability that an even number (2, 4 or 6) will occur more than 6 times?
A. 0.8281
B. 0.2051
C. 0.1719
D. 0.1172
E. 0.9453
3. Which one of the following statements is not a necessary assumption of the binomial distribution?
A. Trials are independent of each other
B. Sampling is with replacement
C. The experiment consists of n identical trials
D. The probability of success remains constant from trial to trial
E. Each trial results in one of two mutually exclusive outcomes
4. If p = 0.65 and n = 20, then the corresponding binomial distribution is
A. Symmetric
B. Bimodal
C. Right skewed
D. Left skewed
5. In the most recent election, 20% of all eligible college students voted. If a random sample of 20 students were surveyed:
Find the probability that less than five students voted in the election.
A. 0.1746
B. 0.2182
C. 0.3704
D. 0.6296
Part -2:
6. The area under the normal curve between z = 0 and z = -1 is ________________ the area under the normal curve between z = -2 and z = -3.
A. Greater than
B. Less than
C. Equal to
D. A, B or C above dependent on the value of the mean
E. A, B or C above dependent on the value of the standard deviation
7. 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 is the probability that less than 30 accounts will be classified as delinquent?
A. 31.86%
B. 18.14%
C. 81.86%
D. 63.72%
E. 75.84%
Part -3:
8. A manufacturing company measures the weight of boxes before shipping them to the customers. If the box weights have a population mean and standard deviation of 90 lbs. and 24 lbs. respectively, then based on a sample size of 36 boxes, the probability that the average weight of the boxes will be greater than 94 lbs. is:
A. 34.13%
B. 84.13%
C. 16.87%
D. 56.36%
E. 15.87%
9. 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 13 percent of the accounts are delinquent. For this quarter, the auditing staff randomly selected 250 customer accounts. What is the probability that less than 40 accounts will be classified as delinquent?
A. 42.07%
B. 40.15%
C. 90.15%
D. 92.07%
E. 7.93%
Part -4:
10. The width of a confidence interval will be:
A. Wider for 90% confidence than for 95% confidence
B. Narrower for 99% confidence than for 95% confidence
C. Wider for a sample size of 100 than for a sample size of 150
D. Wider when the sample standard deviation (s) is small than when s is large
11. When the level of confidence and sample size remain the same, a confidence interval for a population proportion p will be __________ when p(1-p) is smaller than when p(1-p) is larger.
A. Narrower (Interval = sample proportion ± z*( p(1-p)/n)^.5, so that smaller is p(1-p) smaller is interval)
B. Wider
C. Neither A nor B, they will be the same
D. Cannot tell from the information given
12. In a manufacturing process a random sample of 16 bolts manufactured has a mean length of 8 inches with a standard deviation of 1.6 inches. What is the 99% confidence interval for the true mean length of the bolt?
A. 6.970 to 9.030
B. 7.216 to 8.784
C. 7.147 to 8.853
D. 2.715 to 12.715
E. 6.821 to 9.179
13. 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). For this quarter, the auditing staff randomly selected 400 customer accounts and found that 120 of these accounts were delinquent. What is the 90% confidence interval for the proportion of all delinquent customer accounts at this manufacturing company?
A. 0.255 to 0.345
B. 0.262 to 0.338
C. 0.241 to 0.359
D. 0.250 to 0.350
14. The internal auditing staff of a local manufacturing company performs a sample audit each quarter to estimate the proportion of accounts that are current (between 0 and 60 days after billing). The historical records show that over the past 8 years 60 percent of the accounts have been current. Determine the sample size needed in order to be 99% confident that the sample proportion of the current customer accounts is within .03 of the true proportion of all current accounts for this company.
A. 1842
B. 1549
C. 722
D. 1025
E. 1770