Question

A juice shop owner wants to know the average amount of juice his staff puts into each glass. A sample of 50 glasses was found to have an average (mean) of 245 ml. If the known standard deviation of the amount of juice in each glass is 4 ml for the entire population, what is the margin of error of the sample mean?

a)1.13 ml
b)1.24 ml
c)1.35 ml
d)1.49 ml

Answer 1

so its A) 1.13 they should ask you for a margin of error that is within some sort of range if we wanted a margin of error of 2% .... etc .02 = z(.5657) z = 2/(56.57) or about .04 but thats usually not what is asked. they usually want to know what size sample we should get to be say 95% confident that the margin of error is with 2% .02 = 1.96(4/sqrt(n)) and we can solve for n

Answer 2

The correct answer is

A- 1.13 ml

:)