Question

Suppose that many large samples are taken from a population and that the sample proportions are normally distributed, with a mean of 0.22 and a standard deviation of 0.029. 99.7% of the sample proportions will fall within which of the following intervals?

A. 0.133 to 0.307
B. 0.104 to 0.366
C. 0.162 to 0.278
D. 0.191 to 0.249

Answer 1

@perl is this like the other problem you helped me with but in reverse?

http://openstudy.com/study#/updates/552f320ae4b0863033976526

Answer 2

yes it is similar

Answer 3

thanks for linking that

Answer 4

no problem thank you for your help all the time. do I still use the same formula?

Answer 5

yes we can use that formula (for sample proportions)

Answer 6

is n the standard deviation or sample size?

Answer 7

because here the standard deviation is 0.029

Answer 8

according to the empirical rule, within 3 standard deviations 99.7% of the data falls inside it.
so we can use 3 for our z critical score

Answer 9

I thought is was .997

Answer 10

actually the z score is more like 2.96 but

Answer 11

do I multiply the .022 times the .029 I am a little confused on the +-3

Answer 12

$$
\Large \rm {
\\ p \pm Margin~of~Error
\\ p \pm Z_{critical} * (standard~ deviation)
\\ 0.22 \pm 3 \times0.029
\\ ( 0.22 - 3 \times0.029, 0.22 + 3 \times0.029)
\\ ( .133, .307)
}
$$

Answer 13

srry I lost connection

Answer 14

so that would make the answer a. then