Question

Determine the point estimate of the population mean and the size of the margin of error for a 90% confidence interval whose lower bound is 14 and whose upper bound is 22. The point estimate of the population mean is The margin of error for the confidence interval is

Answer 1

Solution :

given that

Lower confidence interval = 14

Upper confidence interval = 22

$\bar x$  = (Lower confidence interval + Upper confidence interval ) / 2

$\bar x$ = ( 14+ 22) / 2

POINT ESTIMATE (Sample mean) = $\bar x$ =18

Margin of error = E = Upper confidence interval - $\bar x$

= 22-18

Margin of error = E  =4