Final answer:
The most appropriate test for comparing satisfaction ratings of the same group of employees before and after switching catering services is a paired t-test, with the alternative hypothesis stating that there is a significant difference in satisfaction ratings.
Step-by-step explanation:
Hypothesis Testing for Matched or Paired Samples
Since Dan sent out the same satisfaction survey to the same group of employees before and after switching the catering company, the most appropriate test for this scenario is a paired t-test (also known as a matched pairs t-test). A paired t-test is used when you have two sets of related observations, like the same group of employees rating two different catering companies.
The null hypothesis, in this case, would typically state there is no difference in the satisfaction ratings, while the alternative hypothesis would be that there is a significant difference. Because Dan is interested in whether there is any change (not necessarily if one is better than the other), the alternative hypothesis (Ha) should be non-directional, which is stated as there being a nonzero difference in satisfaction ratings. Thus, the correct hypothesis and test choice would be: Paired t-test with Ha: difference ≠ 0.