Assume a telephone company has created a dataset for a representative sample of its customers. The company wishes to test its belief that the mean number of customer service calls is different between customers who churn (i.e., leave the company) and those who stay.

a) State the null and alternate hypothesis for this test.

The tables below show the results for a two sample t-test to compare the means of the number of customer service calls between the two groups.

Churn	Mean	95% CL Mean	Std Dev	95% CL Std Dev
No	1.45	1.41	1.49	1.16	1.13	1.19
Yes	2.23	2.06	2.40	1.85	1.74	1.98

Variance Assumption	Df	t Value	p-Value
Equal Variances Assumed	3331	-12.32	<.0001
Equal Variances Not Assumed	548.17	-8.96	<.0001

Levene Test for Equality of Variances
F Value	p-Value
2.54	<.0001

b) Is it valid to assume that the variances in the two groups are equal? Explain your answer.

c) Which t-test should be used to test the hypothesis? Explain.

d) Should the null hypothesis be rejected? Explain.