Question

A bank estimated that the standard error for a 95% confidence interval for the proportion of a certain demographic group that may default on a loan is 0.31. The lower confidence limit was calculated as 0.15. What is the upper confidence limit?

Answer 1

Solution :

Given that,

lower limit = 0.15

E = 0.31

A 95% confidence interval for population proportion p is ,

= lower limit + E

= 0.15 + 0.31

= 0.46

upper limit =   + E

upper limit = 0.46 + 0.31

upper limit = 0.77