Answer:
The critical value for the 90% confidence interval is .
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of , and a confidence level of , we have the following confidence interval of proportions.
In which
z is the z-score that has a p-value of .
90% confidence level
So , z is the value of Z that has a p-value of , so .
The critical value for the 90% confidence interval is .