q1. 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 70 patients will not be satisfied with the after-surgery care?

a. 78.88

b. 89.44

c. 39.44

d. 10.56

e. 84.49

q2. In a manufacturing process, a random sample of 9 bolts manufactured has a mean length of 3 inches with a standard deviation of .3 inches. What is the 95% confidence interval for the true mean length of the bolt?

a. 2.904 to 3.396

b. 2.412 to 3.588

c. 2.884 to 3.086

d. 2.770 to 3.231

e. 2.308 to 3.692

q3. A response bias (measurement error) cannot be more in Census than in Sample.

True or False

q4. If a one-sided null hypothesis is rejected at a given significance level, then the corresponding two-sided null hypothesis (the same sample size, the same standard deviation, and the same mean) will be ____________________ rejected at the same significance level.

a. never

b. always

c. sometimes

q5. If p=.8 and n=50, then we can conclude that the sampling distribution of the proportions is approximately a normal distribution.

True or False

q6. In a two tailed test, if the p value is less than the significance level alpha, then:

a. H0 is rejected

b. additional information needed and no conclusion can be reached on whether H0 is rejected or not

c. H0 may or may not be rejected depending on the sample size

d. H0 is not rejected

q7. When the sample size and sample standard deviation remain the same, a 90% confidence interval for a population mean, will be narrower than the 95% confidence interval for .

True or False

q8. If we have a sample size of 100 and the estimate of the population proportion is .10, the standard deviation of the sampling distribution of the sample proportion is:

a. 0.03

b. 0.009

c. 0.10

d. 0.01

q9. The standard deviation of the binomial distribution is np(1-p)

True or False

q10. In a study conducted by UCLA, it was found that 25% of college freshman support increased military spending. If 6 college freshmen are randomly selected, find the probability that exactly 3 support increased military spending.

a. 0.0330

b. 0.7844

c. 0.1318

d. 0.9624