Question

Construct a 90​% confidence interval of the population proportion using the given information. x=120, n=300

The lower bound is____

The upper bound is_____

​(Round to three decimal places as​ needed.)

Answer 1

Let 'p' be the proportion of members of members with a characteristic A in a population. Let X be the number of members with characteristic A in a random sample of size n=300.
Then X~ Bin(n,p) and estimate of p is given by sample proportion of characteristic A,  

This has mean

Confidence interval:

The lower bound:

The upper bound: