Suppose a 90% confidence interval for the mean salary of college graduates in a

Question

Suppose a 90% confidence interval for the mean salary of college graduates in a town in Mississippi is given by [$30,880, $40,720]. The population standard deviation used for the analysis is known to be $15,000.

a.

What is the point estimate of the mean salary for all college graduates in this town?

  Point estimate

b.

Determine the sample size used for the analysis.

  Sample size

Suppose a 90% confidence interval for the mean salary of college graduates in a town in Mississippi is given by [$30,880, $40,720]. The population standard deviation used for the analysis is known to be $15,000.

Explanation / Answer

a. Here it is given that x-E=30880 and x+E=40720

So 2x=40720+30880=71600

Hence x=35800

Further x-E=30880

b. So E=35800-30880=4920

Now z=1.645

E=z*sd/sqrt(n)

So n=(z*sd/E)^2=25

Related Questions

Navigate

• Browse (All)
• Browse S
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.