Question

The mean per capita consumption of milk per year is 140 liters with a standard deviation of 22 liters. If a sample of 233 people is randomly selected, what is the probability that the sample mean would be less than 137.01 liters? Round your answer to four decimal places.

Answer 1

Sol

mean=140

std =22

n=233

sample sd=22/sqrt(233)=1.441268

here n>30 large sample ,hence follows normal distribution

X bar~N(140,1.441268)

e probability that the sample mean would be less than 137.01 liters

P(Xbar<137.01)

P(Z<137.01-140/1.441268)

P(z<-2.0746)

=0.019

ANSWER:

0.0190