Suppose a researcher interested in obtaining an estimate of

Suppose a researcher, interested in obtaining an estimate of the average length of some enzyme in a certain human population, takes a sample of 10 individuals, determines the level of the enzyme in each, and computes a sample mean of X = 22. Suppose further it is known that the variable of interest is approximately normally distributed with a population standard deviation of = 6.7. Find the UPPER confidence limit in the 95% confidence interval for .

A) 17.21

B) 17.84

C) 26.79

D) 26.15

Solution

upper confident limit

alpha = 1 -0.95 = 0.05

alpha / 2 = 0.025

Z = 1.96

I : xbar + Z * sigma / srqt (N)

I : 22 + 1.96 * 6.7 / sqrt (10)

I : 22 + 4.15

I : 26.15

I :