The standard deviation of a population is known to be 7.8. If The sample size is 85, what is the standard error of the mean?

1) 0.22

2) 0.85

3) 1.047

4) 6.008

The given standard deviation of a population (σ) = 7.8

sample size (N) = 85

We have to find standard error of the mean.

The formula to find standard error of the mean

= (standard deviation of the distribution) / (square root of sample size)

= (σ) / (√N)

= 7.8 / (√85)

= 7.8 / 9.219544457

= 0.8460

= 0.85 (approximately taken to two decimal places)

We have got the required answer.

The standard error of the mean is 0.85.