Answer:
The minimum sample size is 610.
Step-by-step explanation:
We have that to find our level, that is the subtraction of 1 by the confidence interval divided by 2. So:
Now, we have to find z in the Ztable as such z has a pvalue of .
So it is z with a pvalue of , so
Now, find M as such
In which is the standard deviation of the population and n is the size of the sample.
Population standard deviation is $6300, so
Suppose we want to determine the minimum sample size required to give us a 95% confidence interval that estimates, to within $500, the average salary of a state employee.
This is n when M = 500. So
Rouding up
The minimum sample size is 610.