Question32

When drawn from a normal distribution, 95% of the sample means will fall within how many standard deviations of the population mean?

Select one:

a. 1.44

b. 1.96

c. 2.25

d. 2.58

Question34

A regression analysis suggests that the number of children an employee has predicts the number of personal days he/she will take off of work. The slope of the regression line is 3.2, and the lower bound of the confidence interval for this slope is 0.8. What is the upper bound?

Select one:

a. 4.0

b. 4.2

c. 5.2

d. 5.6

Question36

In a statistical analysis, how does the t-distribution differ from the z-distribution?

Select one:

a. It has a smaller standard deviation.

b. It does not assume normality.

c. It depends on sample size.

d. It is a discrete distribution.

Question39

A researcher tests the hypothesis that math scores are significantly different between two groups of students. The test yields a p-value of 0.01. What is the correct interpretation of this value?

Select one:

a. There is a 1% likelihood that the difference was due to chance.

b. The two score distributions have common values 1 percent of the time.

c. The result has a 99% probability of being replicated.

d. The test results were 99% different between the two groups.

Question40

A class of 25 students took a reading test before and after completing an intensive vocabulary course to determine whether there was a change in scores in either direction. The mean pre-test score was 24, and the mean post-test score was 32. The standard deviation of the difference was 9. What value of the t-statistic does this difference correspond to?

Select one:

a. 1.7

b. 2.9

c. 4.4

d. 5.6