Question

x =30 n=2323​, σ=66​, confidence =90​%

a. Use the​ one-mean z-interval procedure to find a confidence interval for the mean of the population from which the sample was drawn.

The confidence interval is from to

b. Obtain the margin of error by taking half the length of the confidence interval.

What is the length of the confidence​ interval?

c. Obtain the margin of error by using the formula E=z(a/2) x o/ square root of n

Identify the critical value.

What is the margin of error obtained using the methods of parts​ (b) and​ (c)?

Answer 1

a) a 90% confidence interval for the mean of the population

*20.05, (a 20.05 n

6 (30 *20.05, 30 20.05 23 23

1.64485) V23 (30 1.64485, 30 V23

=(27.9422, 32.0578)

b) The length of the confidence interval = 32.0578 - 27.9422 = 4.1156

The margin of error

4.1156 2.0578 2.

c) At 90% confidence level, critical value

Ecritical= 20.05= 1.64485)

Margin of error

6 - 1.64485 2.05785 23 20,05