According to the IRS, the average refund in the 2011 tax year was $3,109. Assuming that the standard deviation for these refunds was $874, what is the standard error of the sample mean for a random sample of 36 tax returns?
a. 74.66
b. 145.67
c. 100.56
d. 123.60
Solution :
Given that,
mean =
= 3109
standard deviation =
= 874
n = 36
The sample mean =
= 3109
The standard error of the sample mean =
=
/
n
= 874
36
= 145.6667
= 145.67
Option b ) is correct.
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