Reference no: EM132880101

You're a HR analyst for Charles Schwab. You want to see if there a difference in employee satisfaction on a survey between newly hired employees (within the past 2 years) and employees that have worked for the company for a long period of time (5 or more years).

Newly Hired Worked at Company for a Long Period of Time

Number 21 25

Mean 3.57 2.53

Std Dev 1.30 1.16

a) Assuming equal variances, is the result significant at the .05 level, with a two-tailed test?

b) Approximately, what is the one-tailed critical t value at the .05 level?

c) What can you conclude from the result of a)?

d) Calculate the Separate variance t test and determine if it is significant at the .05 level two tailed?

e) If you decided on an effect size of 1.5 and wanted to run 15 subjects in the newly hired and 10 in the older groups, what would your power be at alpha = .05 two tailed?

f) If d was 1.5, how many subjects would you need in each group to attain power = .80, two tailed test at alpha = .05, assuming the sizes of the two groups are equal?

g) Find the 95% confidence interval for the difference of the two population means. Explain how this CI relates to your answer in a).