Question

Karen wants to advertise how many chocolate chips are in each Big Chip cookie at her bakery. She randomly selects a sample of 60 cookies and finds that the number of chocolate chips per cookie in the sample has a mean of 15.9 and a standard deviation of 1.8. What is the 99% confidence interval for the number of chocolate chips per cookie for Big Chip cookies? <μ<
Enter your answers accurately to one decimal place.

Answer 1

Sample mean : \overline{x}=10.6x=10.6

Standard deviation : s=1.7s=1.7

Significance level : \alpha:1-0.95=0.05α:1−0.95=0.05

Critical value : z_{\alpha/2}=1.96

Hence the 95% confidence interval for the number of chocolate chips per cookie for big chip cookies= (10.1989,\ 11.0011)(10.1989, 11.0011)