A restaurant claims their customers spend on average 75 minutes at their restaurant with a standard deviation of 13. The restaurant manager has also confirmed that the distribution of time spent in the restaurant is normally distributed.

1. a)Suppose your visit is 90 minutes due to a high volume of diners. Is there any reason to believe that the restaurant manager's claim is false? Use a z-score to justify your answer. (1 mark)
2. b)Suppose your waiting time is 120 minutes. Is there any evidence that the claim is false now? (1 mark)