Question

Use the formula to find the standard error of the distribution of differences in sample means,x¯1-x¯2.

Samples of size 120 from Population 1 with mean 81 and standard deviation 13 and samples of size 70 from Population 2 with mean 73 and standard deviation 15

Round the standard error to two decimal places.

Answer 1

s1 = 13 , n1 = 120
s2 = 15 , n2 = 70

std.error = sqrt(s1^2/n1+s2^2/n2)
= (13^2/120 + 15^2/70)
= 4.62