the manager of a restaurant in a large city claims that waiters working in all restaurants in his city earn an average of $157 or more in tips per week. a random sample of 27 waiters selected from restaurants of this city yielded a mean of $147 in tips per week with a standard deviation of $29 (sample standard deviaiton). assume that the weekly tips for all waiters in this city have a normal distribution. using a 2.5% significance level, can you conclude that the manager's claim is false? use the critical-value approach. round your observed value to two decimal places. observed value or test statistic of t =