Answer:
3.625
Explanation:
Given a normal distribution :
Average weight = population mean = 172 pounds
Population standard deviation = 29 pounds
Number of samples selected(n) = 64
The standard deviation of the sample also called the standard error is the proportion of the population standard deviation to the square root of the number samples.
Sample standard deviation :
Population standard deviation /√n
= 29 /√64
= 29 / 8
= 3.625