Question

A sample of 81 was taken from a population with a standard deviation of 45 kilograms. If the sample mean was 112 kilograms, the mean of any other sample of 81 will be within what range 95% of the time?

A. 97 kilograms to 127 kilograms
B. 92 kilograms to 132 kilograms
C. 102 kilograms to 122 kilograms
D. 107 kilograms to 117 kilograms

Answer 1

@prettygirl876

Answer 2

L = xbar - z*s/sqrt(n)
U = xbar + z*s/sqrt(n)


xbar = sample mean
s= standard deviation
z = critical value

Answer 3

what would (n) be?

Answer 4

is 81 the critical value?

Answer 5

n = sample size

Answer 6

z = 2 is the critical value because 95% of the data is within 2 std dev of the mean

Answer 7

so would it be set up like this:?

112-2*45/sqrt81

112+2*45/sqrt81

Answer 8

@jim_thompson5910

Answer 9

yes

Answer 10

The first one looks like 102 and the second 122 which would be C.?

Answer 11

thank you :)