Answer:
So the answer for this case would be n=737 rounded up to the nearest integer
Step-by-step explanation:
We have the following info given:
the sample mean
the sample deviation
represent the sample size
The degrees of freedom are given by:

The margin of error is given by this formula:
(a)
And on this case we have that ME =0.25 and we are interested in order to find the value of n, if we solve n from equation (a) we got:
(5)
The confidence level is 95% and the critical value for this case would be given by
, replacing into formula (5) we got:
So the answer for this case would be n=737 rounded up to the nearest integer
18/50 is an equivalent fration because when simplified it equals to 9/25