Question

A study of a random sample of 50 of the technicians conducted in a company that employs 800 technicians shows that the average sample age is 34.30 years. Historically the population standard deviation of the age of the company's employees is approximately 8 years. Construct a 98% confidence interval to estimate the average age of all engineers in the company.

Answer 1

Answer

Step 1

given:

n=50

mean age = 34.3

standard deviation = 8

to find 98% confidence interval of average age.

Step 2

confidence interval is calculated by the following formula,

= x± $σ \over √n$ x $Z {_α\over 2}$

=34.3 ± $8 \over √50$x 2.33 =(31.664,36.936)

 

98% confidence interval for average age is (31.664,36.936).