Answer:
a)
And rounded up we have that n=4906
b) For this case since we don't have prior info we need to use as estimatro for the proportion
And rounded up we have that n=6724
Step-by-step explanation:
We need to remember that the confidence interval for the true proportion is given by :
Part a
The estimated proportion for this case is
Our interval is at 90% of confidence, and the significance level is given by and
. The critical values for this case are:
The margin of error for the proportion interval is given by this formula:
(a)
The margin of error desired is given and we are interested in order to find the value of n, if we solve n from equation (a) we got:
(b)
Replacing we got:
And rounded up we have that n=4906
Part b
For this case since we don't have prior info we need to use as estimatro for the proportion
And rounded up we have that n=6724