Question

Karen wants to advertise how many chocolate chips are in each Big Chip cookie at her bakery. She randomly selects a sample of 78 cookies and finds that the number of chocolate chips per cookie in the sample has a mean of 15.8 and a standard deviation of 1.9. What is the 95% confidence interval for the number of chocolate chips per cookie for Big Chip cookies? Enter your answers accurate to one decimal place because the sample statistics are reported accurate to one decimal place) <HT
help!

Answer 1

sample mean 'x̄=	15.800
sample size    n=	78.00
std deviation s=	1.900
std error ='sx=s/√n=	0.2151

for 95% CI; and 77 df, value of t=		1.9910
margin of error E=t*std error    =		0.428
lower bound=sample mean-E =		15.372
Upper bound=sample mean+E =		16.228
from above 95% confidence interval for population mean =(15.4 <μ< 16.2)