Stat 2300 Activities 58

Thus we have a strong evidence to conclude that mean time of auditing delay is lesser after the merger. However at 99% confidence level the null hypothesis cannot be rejected since the p-value is greater than 1%.
For Problem # 1, we conducted a z-test for mean differences since both of the independent samples were greater than 30. For Problem # 2, it was valid to use a one-tail t-test for mean differences since the samples were smaller than 30 and we also assumed unequal variances since the question did not mention