A department store manager wants to estimate the average number of customers who enter the store every 5 minutes. She randomly selects 5-minute intervals and counts the number of arrivals at the store. A random sample of 10 five-minute intervals reveals the mean number of customers who enter the store every 5-minutes to be 12 with a standard deviation of 2. Assume the population distribution is normal.Develop a 99% confidence interval. (Round all answers and calculations 2 decimal points.) (include all formulas, identify all variables, show all calculations, and draw and shade your distributions)

1. Develop a 99% confidence interval

Identify the following variables. If a variable is unknown enter unknown (all lower case) as your answer.

a. sample mean =

b. standard deviation =

c. sample size =

d. t =

Confidence interval

e. lower limit

f. upper limit