Question

According to a study of political​ prisoners, the mean duration of imprisonment for 30 prisoners with chronic​ post-traumatic stress disorder​ (PTSD) was 32.6 months. Assuming that sigmaσequals=4545 ​months, determine a 95​% confidence interval for the mean duration of​imprisonment,μ​, of all political prisoners with chronic PTSD. Interpret your answer in words.

confidence level interval for 95%

Answer 1

Answer)

As the population standard deviation is known here, we can use standard normal z table to estimate the interval

Given mean = 32.6

S.d = 45

Critical value z for 95% confidence level is 1.96

Margin of error = z*(s.d/√n)

N = sample size = 30

MOE = 16.1030431906

Confidence interval is given by

(Mean - MOE, Mean + MOE)

(16.4969568093, 48.7030431906)

We are 95% confident that true population mean lie in this interval