Question

Karen wants to advertise how many chocolate chips (in grams) are in each Big Chip cookie at her bakery. She randomly selects a sample of 10 cookies and finds that the number of chocolate chips per cookie in the sample has a mean of 58.7 and a standard deviation of 41.2. What is the 90% confidence interval for the number of chocolate chips per cookie for Big Chip cookies?

• 47 < μμ < 70.4
• 24.6 < μμ < 92.8
• 14.4 < μμ < 103
• 34.8 < μμ < 82.6
• 51.5 < μμ < 65.9

Answer 1

Solution :

Given that,

t /2,df = 1.833

Margin of error = E = t/2,df * (s /n)

= 1.833 * (41.2 / 10)

Margin of error = E = 23.9

The 90% confidence interval estimate of the population mean is,

- E < < + E

58.7 - 23.9 < < 58.7 + 23.9

34.8 < < 82.6