In: Statistics and Probability
A simple random sample of size n is drawn from a population that is normally distributed. The sample mean, x, is found to be 111, and the sample standard deviation, s, is found to be 10.
(a) Construct a 98% confidence interval about μ if the sample size, n, is 15.
(b) Construct a 98% confidence interval about μ if the sample size, n, is 23.
(c) Construct a 99% confidence interval about μ if the sample size, n, is 15.
(d) Could we have computed the confidence intervals in parts (a)-(c) if the population had not been normally distributed?
Anything helps!
a)
b)
c)
d) No, since sample sizes are not large enough ( > 30) to approximate the sampling distribution of sample mean by normal distribution, usingg Central limit theorem.