Question

A 90% confidence interval for the proportion of coffee drinkers that add sugar and creme has results in the following output:

one sample proportion summary confidence interval:

p: proportion of success

method:standard-wald

90% confidence interval results:

proportion: p

count:1136

total:1803

sample prop: 0.63006101

std. edrr.: 0.011369948

l. limit: 0.61135911

u. limit: 0.6487629

a. Identify the values for n, p, ˆ q, ˆ and E.

b. Write a statement that interprets the 90% confidence interval

Answer 1

An alternative way to calculate margin of error that is E is

( l. Limit + u. Limit )/2

= ( 0.61135911 + 0.6486629 )/2

= 0.018702