a. The key to solving this problem is to recognize that 171 and 183 are each exactly 1 standard deviation away from the mean of 177. Therefore, 1 standard deviation from the mean is:
[tex]\begin{gathered} 177-6=171 \\ 177+6=183 \end{gathered}[/tex]The empirical rule tells us that about 68% of all values are within 1 standard deviation of the mean, so about 68% of men are between 171 cm and 183 cm.
b.
