Question

Annual starting salaries for college graduates with degrees in business administration are generally expected to be between $39,000 and $56,800. Assume that a 95% confidence interval estimate of the population mean annual starting salary is desired. (Round your answers up to the nearest whole number.)

What is the planning value for the population standard deviation?

(a)

How large a sample should be taken if the desired margin of error is $600?

(b)

How large a sample should be taken if the desired margin of error is $200?

(c)

How large a sample should be taken if the desired margin of error is $100?

(d)

Would you recommend trying to obtain the $100 margin of error? Explain.

Answer 1

planning value =range/4 =(56800-39000)/4=4450

a)

	for95% CI crtiical Z          =	1.960
	standard deviation σ=	4450
	margin of error E =	600
required sample size n=(zσ/E)2                  =		212

b)

	for95% CI crtiical Z          =	1.960
	standard deviation σ=	4450
	margin of error E =	200
required sample size n=(zσ/E)2                  =		1902

c)

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

7608

d)

as that margin of require cost a lot to sample as well this must accuracy might not be required