In a random sample of 144 observations, $\bar { p }$ = .6.The 95% confidence interval for p is
A) .52 to .68.
B) .14 to .20.
C) .55 to .65.
D) .50 to .70.

Question

Quizplus · Accepted Answer

The 95% confidence interval for p is given by:$\bar { p } \pm 1.96 \sqrt { \frac { \bar { p } ( 1 - \bar { p } ) } { n } }$Plugging in the values we get:.6 ± 1.96 \sqrt { \frac { .6 ( 1 - .6 ) } { 144 } } = .6 ± 1.96 \sqrt { \frac { .6 ( .4 ) } { 144 } } = .6 ± 1.96 \sqrt { \frac { .24 } { 144 } } = .6 ± 1.96 \sqrt { \frac { .001667 } { } } = .6 ± 1.96 \sqrt { .001667 } = .6 ± 1.96 ( .0408 ) = .6 ± .08 = .52 to .68

In a Random Sample of 144 Observations pˉ\bar { p }pˉ​

In a Random Sample of 144 Observations $\bar { p }$