posted by haley .
A sample of 65 night-school students' ages is obtained in order to estimate the mean age of night-school students. x bar = 25.2 years. The population variance is 28.
(a) Give a point estimate for ì. (Give your answer correct to one decimal place.)
Correct: Your answer is correct. .
(b) Find the 95% confidence interval for ì. (Give your answer correct to two decimal places.)
Lower Limit Incorrect: Your answer is incorrect. .
(c) Find the 99% confidence interval for ì. (Give your answer correct to two decimal places.)
a. 25.2 years
b. Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability
(±.025) and its Z score.
95% = mean ± Z SEm
SEm = SD/√n
SD = √variance
c. Same process with ±.005.