Question

marketing research company desires to know the mean consumption of meat per week among people over age 31. A sample of 369 people over age 31 was drawn and the mean meat consumption was 2.4 pounds. Assume that the population standard deviation is known to be 0.7 pounds. Construct the 85% confidence interval for the mean consumption of meat among people over age 31. Round your answers to one decimal place. Lower endpoint- High endpoint-

Answer 1

Solution:-
given
marketing research company desires to know the mean consumption of meat per week among people over age 31.
A sample of 369 people over age 31 was drawn and the mean meat consumption was 2.4 pounds. Assume that the population standard deviation is known to be 0.7 pounds.
therfore
mean = 2.4 ,
sd =0.7 ,
n = 369
by using z value calculator
Z = 1.44
85% confidence interval for the mean :
X +/- Z * s/sqrt(n)
= 2.4 +/- 1.44*0.7/sqrt(369)
= 2.4 +/- 1.008/19.2
= 2.4 +/- 0.0525
= (2.3475 , 2.4525)
therefore
Lower endpoint = 2.3

Upper endpoint = 2.5