In a study of 24 criminals convicted of antitrust offenses, the average age was 60 years, with a standard deviation of 7.4 years. Construct a 95% confidence interval on the true mean age. (Give your answers correct to one decimal place.)___ to years

56.9 years to 63.1 years.

Step-by-step explanation:

Confidence interval for population mean (when population standard deviation is unknown):

, where = sample mean, n= sample size, s= sample standard deviation, = Two tailed t-value for .

Given: n= 24

degree of freedom = n- 1= 23

= 60 years

s= 7.4 years

Two tailed t-critical value for significance level of and degree of freedom 23:

A 95% confidence interval on the true mean age:

Hence, a 95% confidence interval on the true mean age. : 56.9 years to 63.1 years.