Question

Time spent using e-mail per session is normally distributed with a mean = to 8 minutes and standard deviation = 2minutes. If a random samples of 36 sessions were selected, the computed sample standard deviation would be

a. 0.25
b. 0.3333
c. 0.42
d. 0.48

Answer 1

The correct option is (b) 0.3333.

Explanation:

The standard deviation of the sampling distribution of sample mean
`(\bar x)` is known as the standard error
`(\sigma_(\bar x))`.

The standard error is given as follows:

`\sigma_(\bar x)=(\sigma)/(√(n))`

The information provided is:

`\mu=8\\\\\sigma=2\\\\n=36`

Compute the standard deviation of the sample mean as follows:

`\sigma_(\bar x)=(\sigma)/(√(n))`

`=(2)/(√(36))\\\\=(2)/(6)\\\\=(1)/(3)\\\\=0.3333`

Thus, the standard deviation of the sample mean is 0.3333.