Question

Suppose​ 30% of the people in your town talk on their cell phones and drive at the same time. If you stood on a busy street corner and watched 50 people drive​ by, what is the standard deviation of the model you would use for the sample proportion you​ observe?

Answer 1

`SD= 3.24`

Explanation:

Given

`Proportion, p = 30\%`

`Population, n = 50`

Required

Determine the standard deviation

Standard Deviation (SD) is calculated as:

`SD= √(np(1-p))`

Substitute values for n and p

`SD= √(50 * 30\% * (1-30\%))`

Convert percentage to decimals

`SD= √(50 * 0.30 * (1-0.30))`

`SD= √(50 * 0.30 * 0.70)`

`SD= √(10.5)`

`SD= 3.24` approximated