A simple random sample of size n is drawn from a population that is normally distributed. The sample mean, x, is found to be 112, and the sample standard deviation, s, is found to be 10.
(a) Construct an 80% confidence interval about u if the sample size, n, is 25
(b) Construct an 80% confidence interval about u if the sample size, n,
is 15.
(c) Construct a 70% confidence interval about u if the sample size, n, is 25.
(d) Could we have computed the confidence intervals in parts (a)-(c) if the population had not been normally distributed?
Click the icon to view the table of areas under the t-distribution.
(a) Construct an 80% confidence interval about u if the sample size, n, is 25.
Lower bound: Upper bound:
(Use ascending order. Round to one decimal place as needed.)