Question

You are researching the average emails received per day. You want to know how many employees you should survey if you want to know, at a 90% confidence level, that the sample mean emails per day is within 47 emails of the true mean emails per day. From above, we know that the population standard deviation is 155, and z-value is 1.645$_

Answer 1

The value is
`n =29 \ employees`

Explanation:

Generally the number of employee to survey(sample size) is mathematically represented as

`n = [ (z *  \sigma )/(E) ]^2`

Here E is the margin of error which is given as E = 47

So substituting 1.645 for z and 155 for
`\sigma`

`n = [ (1.645 *  155 )/(47) ]^2`

=>
`n =29 \ employees`