Chipotle is looking to reduce its long line by speeding up how long it takes to make a burrito bowl on average

Chipotle is looking to reduce its long line by speeding up how long it takes to make a burrito bowl on average. Look at the Chipotle data tab which shows the average time it took to make a burrito bowl for 200 randomly observed customers during the lunch rush-hour. 

a) Make a 95% two-sided confidence interval for the true average service time for making a burrito bowl during a lunch rush hour. Show your calculation OR statistical software results and interpret your results.

b) Chipotle is okay if just a few customers have a slow experience. They would like to know what proportion of customers will experience a service time of 2 minutes or more. Construct a 95% two-sided confidence interval for the proportion of customers that will experience a service time of 2 minutes or more for their burrito bowl during rush hour. Show your calculation OR statistical software results and interpret your results. 

Note: you may want to make a dummy variable to categorize customers that experience this service time.