Hypothesis testing for difference between two population means.
1. A researcher randomly sampled 30 graduates of an MBA program and recorded data concerning their starting salaries. Of primary interest to researcher was the effect of gender on starting salaries. Analysis of the mean salaries of the females and males in the sample is given below.
Hypothesized Difference

0

Level of Significance

0.05

Population 1 Sample


Sample Size

18

Sample Mean

48266.7

Sample Standard Deviation

13577.63

Population 2 Sample


Sample Size

12

Sample Mean

55000

Sample Standard Deviation

11741.29

Difference in Sample Means

6733.3

tTest Statistic

1.40193

LowerTail Test


Lower Critical Value

1.70113

pValue

0.085962

The researcher was attempting to show statistically that the female MBA graduates have a significantly lower mean starting salary than male MBA graduates. According to the test run, which of the following is an suitable alternative hypothesis?
b. The researcher was attempting to show statistically that the female MBA graduates have a significantly lower mean starting salary than the male MBA graduates. From the analysis in Table 102, the right test statistic is:
1. 0.0860
2. 1.4019
3. 1.7011
4. 6,733.33
2. A real estate company is interested in testing whether, on average, families in Gotham have been living in their current homes for less time than families in Metropolis have. Assume that the two population variances are equal. A random sample of 100 families from Gotham and a random sample of 150 families in Metropolis yield the following data on length of residence in current homes.