Answer: (0.5496, 0.5754)
Explanation:
The confidence interval for population proportion (p) is given by :-
, where
= Sample proportion , n= sample size , z*= Critical z-value.
Let p be the proportion of all college students who are in favor of banning Hawaiian shirt.
Given, A random sample of 4000 college students yielded 2250 who are in favor of banning Hawaiian shirts.
i.e. n=4000

z-value for 90% confidence level is 1.645
Now , 90% confidence interval for p would be :


Hence, the required 90% interval = (0.5496, 0.5754)