A sociologist found that in a random sample of 50 retired men, the average number of jobs they had during their lifetimes was 7.2. The population standard deviation is 2.1.

What variable are you studying?

A. Retirement age

B. Lifetime expectancy

C. Number of jobs in a lifetime

Find the 95% confidence interval of the mean number of jobs. We are 95% confident that the true mean number of jobs is between:

A. 6.0 and 6.5

B. 6.6 and 7.8

C. 6.4 and 7.1

option a is correct.

step-by-step explanation:

scale factor: it is used to find proportional measurements.

proportions means having the same ratio.

scale factor is the ratio of the model measurement to the actual measurement in a simplest form.

or we can say that the ratio of any two corresponding lengths in two similar geometric figures

if the scale factor is more than 1, then it is an enlargement,

if the scale factor less than 1, then it is a reduction.

given the two geometric figure:

by definition of proportions, we have