1. Time spent serving a customer at a cafe is normally distributed, with ? = 7 minutes and ? = 1.8 minutes.

(a) If you select a random sample of duration serving twenty five (25) customers, determine the probability that the sample mean is between 6.8 and 7.2 minutes.

(b) If you select a random sample of 144 customers, determine the probability that the sample mean is between 6.8 and 7.2 minutes.

(c) Explain the difference in the results of (i) and (ii).

2. A factory manager collected a sample of ten (10) packets of 3-in-1 coffee and the weights (in grams) of each packet are recorded as follow:

25 23 26 28 24 21 26 24 25 27City 1 City 2 164 159 01 12.50 02 = 9.25 E 35 30