The owner of a local supermarket wants to estimate the difference between the average number of gallons of milk sold per day on weekdays and weekends. The owner samples 20 weekdays and finds an average of 265.551 gallons of milk sold on those days with a standard deviation of 36.4693. 24 (total) Saturdays and Sundays are sampled and the average number of gallons sold is 370.357 with a standard deviation of 48.9046. Construct a 90% confidence interval to estimate the difference of (average number of gallons sold on weekdays - average number of gallons sold on weekends). Assume the population standard deviations are the same for both weekdays and weekends.

1) (-126.578, -83.034)

2) (-127.07, -82.542)

3) (-126.487, -83.125)

4) We only have the sample means, we need to know the population means in order to calculate a confidence interval.