Point estimate and Poll's margin

Question

The results of a poll show that the percent of people in a town who want an observatory build on a nearby mountain is in the interval (0.60, 0.82). What is the point estimate for the percent of the people in the city who want the observatory? What is the poll's margin of error?

Answer 1

The point estimate of a confidence interval is exactly in the middle of the interval.

To find this value average the lower and upper bound

 

(.6+.82)/2 = .71

 

.71 is the point estimate

 

the margin of error is simply the distance from the point estimate to either lower or upper bound

 

The interval is always 2 margins of error long

 

Therefore we can find by (.82-.6)/2 = .11

 

or ask ourselves, "self" how far is .82 from .71 ??

 

.11 is the MOE