Q4.Home Style pizza of Arizona provides baking instructions for its premade resources. According to the instructions, the average baking time is 12 to 18 minutes. If the times are normally distributed, the standard deviation of the times should be approximately 1-minute. A random sample of 15 pizzas yielded the following baking times to the nearest tenth of a minute.(04 Marks)

15.4

15.1

14.0

15.8

16.0

13.7

15.6

11.6

14.8

12.8

17.6

15.1

16.4

13.1

15.3

a) At the 1% significance level, do the data provide sufficient evidence to conclude that the mean of baking times exceeds 15 minute?

b) Determine a 98% confidence interval for the standard deviation of baking times