Weights of 40 men were obtained from a simple random sample

Weights of 40 men were obtained from a simple random sample. The sample size was 40, the mean weight was 172.55 pounds, and the standard deviation was 26 pounds. Compute the error associated with a 0.95 level of confidence. Round to two decimal places.

Solution

Note that          
          
Margin of error (E) = z(alpha/2) * s / sqrt(n)      

z(alpha/2) = critical z for the confidence interval =    1.959963985      
s = sample standard deviation =    26      
n = sample size =    40      
          
Thus,          
          
Margin of Error =    8.06 [ANSWER]