In a random sample of 651 computer scientists who subscribed to a web-based daily news update, it was found that the average salary was $46,816 with a population standard deviation of $12,557. Calculate a 91 percent confidence interval for the mean salary of computer scientists. Choose the closest value from your table.

And the confidence interval would be given by: (45981.81; 46650.19)

Step-by-step explanation:

Data given

represent the sample mean

population mean (variable of interest)

represent the population standard deviation

n=651 represent the sample size  

Confidence interval

The confidence interval for the mean is given by the following formula:

  (1)

Since the Confidence is 0.91 or 91%, the significacne is   and , and the critical value is

Now we have everything in order to replace into formula (1):

And the confidence interval would be given by: (45981.81; 46650.19)