TABLE 10-2
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.

-Referring to Table 10-2, 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.

Question

TABLE 10-2
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.
 
-Referring to Table 10-2, 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.

Quizplus · Accepted Answer

All of the assumptions mentioned in options A, B, and C are necessary to conduct this hypothesis test. Normality assumption is required for the sampling distributions to be normal. The assumption of equal variances is required to employ the pooled variance t test. The assumption of random and independent sampling is necessary to generalize the findings from the sample to the population.

TABLE 10-2 A Researcher Randomly Sampled 30 Graduates of an MBA Program