Question: A clinic offers a weight-reduction program. A review of its records found the following weight losses, in pounds, for a random sample of 10 clients at the conclusion of the program:

(a) Find a 99% confidence interval for the mean weight losses for clients on this weight reduction program. Is it correct to say at this level that on average people loose at least 13 pounds? Find the maximum level at which we can say this.

(b) Find a 90% confidence interval for the population standard deviation of weight losses for clients of this weight reduction program.

(c) Without doing the calculations, state whether a 95% confidence interval for the pop­ulation standard deviation would be wider than, narrower than, or the same width as that found in (b).

(d) Do we need to assume normality for any of the previous questions?