Question

Annual starting salaries for college graduates with degrees in business administration are generally expected to be between $10,000 and $50,000 . Assume that a 95% confidence interval estimate of the population mean annual starting salary is desired.

a. What is the planning value for the population standard deviation?

= ______

b. How large a sample should be taken if the desired margin of error is ? Round your answer to next whole number.

_______

$270?

_______

$80?

_______

c. Would you recommend trying to obtain the  margin of error? Explain.
- Select your answer -Yes, it always better to be more accurate    No, the sample size would probably be too time consuming and costly

Answer 1

a)

planning value for the population standard deviation =range/4=(50000-10000)/4=10000

b)

for margin of error E =270:

required sample size n=(zσ/E)2                  =

5270

for margin of error E =80

required sample size n=(zσ/E)2                  =

60025 (please try 60023 if this comes wrong and reply)

c)

No, the sample size would probably be too time consuming and costly