Final answer:
Statement a is correct. Statement b is incorrect because it refers to the population variance, not the mean waiting time.
Step-by-step explanation:
The correct statement is a. Reject the null hypothesis and state that there is a difference in the mean waiting time at α=0.01. In hypothesis testing, if the p-value is less than the significance level (α), we reject the null hypothesis. In this case, since α=0.01 and the decision is to reject the null hypothesis, it indicates that there is enough evidence to support the claim of a difference in the mean waiting time. On the other hand, statement b is incorrect because it refers to the population variance, not the mean waiting time.