A random sample of 607 customers in Taco Bell's drive-through results in a mean service time of 163.1 seconds and standard deviation of 24.0 seconds. (a) Obtain a point estimate of mean service time for all customers in Taco Bell's drive through. (b) What is the critical t value for constructing a 90% confidence t-interval? (c) Determine the 90% confidence t-interval. (d) Interpret your confidence interval result in part (c) within the context.