A researcher randomly sampled 30 graduates of an MBA program and recorded data concerning their starting salaries. Of primary interest to the researcher was the effect of gender on starting salaries. The result of the pooled-variance t-test of the mean salaries of the females (Population 1) and males (Population 2) in the sample is given below.

Hypothesized Difference	0
Level of Significance	0.05
Population 1 Sample
Sample Size	18
Sample Mean	99210
Sample Standard Deviation	13577
Population 2 Sample
Sample Size	12
Sample Mean	105820
Sample Standard Deviation	11741
Difference in Sample Means	-6610
tTest Statistic	-1.37631
tTest Statistic
Lower Critical Value	-1.70113
p-Value	0.089816

18. The researcher was attempting to show statistically that the female MBA graduates have a significantly lower mean starting salary than the male MBA graduates. The proper conclusion for this test is:

a) At thea= 0.10 level, there is sufficient evidence to indicate a difference in the mean

starting salaries of male and female MBA graduates.

b) At thea= 0.10 level, there is sufficient evidence to indicate that females have a lower

mean starting salary than male MBA graduates.

c) At thea= 0.10 level, there is sufficient evidence to indicate that females have a higher

mean starting salary than male MBA graduates.

d) At thea= 0.10 level, there is insufficient evidence to indicate any difference in the

mean starting salaries of male and female MBA graduates.

19. The researcher was attempting to show statistically that the female MBA graduates have a significantly lower mean starting salary than the male MBA graduates. What assumptions were necessary to conduct this hypothesis test?

a) Both populations of salaries (male and female) must have approximate normal distributions.

b) The population variances are approximately equal.

c) The samples were randomly and independently selected.

d) All of the above assumptions were necessary.

20. What is the 99% confidence interval estimate for the difference between two means?