A random sample of 49 lunch customers was taken at the restaurant. The average amount of time customers in the sample stayed in restaurant was 33 minutes. From past experience, it is known that population standard deviation is 10 minutes.
a. Evaluate the standard error.
b. With 95% confidence, find out the margin of error?
c. Develop a 95% confidence interval for true average amount of time customers spent in therestaurant.
d. With 95% confidence, how large of sample would've to be taken to give a margin of error of 2.5 minutes or less?