Question

HELP PLEASE:
I am not understanding on how to solve this problem, and a step by step explanation would help a lot.
A random sample of 120 is taken from a population of 10000. From a previous survey, it is believed that 62% of the population has an Instagram account. Find the mean and standard deviation of the sample proportion. Give the standard deviation to two nonzero decimals (such as .012 and not .01).
(mean subscript p-hat) μˆp =

(standard deviation subscript p-hat) σˆp=

Answer 1

Answer: Mean of the sample proportion = 74.4

Standard deviation of the samnple proportion is 5.32.

Step-by-step explanation:

Given : A random sample of 120 is taken from a population of 10000.

Let n = 120

Also, from previous survey, it is believed that 62% of the population has an Instagram account.

i.e, population proportion : p = 0.62

Now , the mean of the sample proportin would be :

$\text{Mean}=\mu_{\hat{p}}=np\\\\=120\times0.62=74.4$

i.e. Mean of the sample proportion = 74.4

The standard deviation of the samnple proportion would be :

$\text{standard deviation}=\sigma_{\hat{p}}=\sqrt{np(1-p)}\\\\=\sqrt{120(0.62)(1-0.62)}\\\\=\sqrt{28.272}\\\\=5.31714208951\approx5.32$

Thus , the standard deviation of the samnple proportion is 5.32.