Question

Construct a 98% confidence interval for the population mean, μ. Assume the population has a normal distribution. A study of 14 car owners showed that their average repair bill was $192 with a standard deviation Round to the nearest cent.

Answer 1

Answer:

(196.97,187.03)

Explanation:  

Formula for Confidence interval is : avg repair bill (a) ± (Z×SD)÷√(sample size)

average repair bill (a) = $192

Z at 98% confidence level = 2.326

Sample Size = 14

Standard Deviation (SD) = $8  

Confidence Interval = 192 ± 2.326*8÷√(14) = {(192 + 4.97),(192 - 4.97)} = {196.97,187.03}