Answer: 0.36
Explanation:
Given : Sample size of spools of wire : n= 24
The sample variance =

The the sample standard deviation should be the square root of the sample variance.
i.e. Sample standard deviation =

Also, the sample standard deviation(s) is the best estimate of population standard deviation
.
Therefore , a point estimate for the population standard deviation
of the diameter of the spools of wire. =s= 0.36
Hence, a point estimate for the population standard deviation of the diameter of the spools of wire= 0.36