(Solved): Selecting appropriate distributions for constructing confladence intervals. You would like to constr ...

Selecting appropriate distributions for constructing confladence intervals. You would like to construct a

confidence interval to estimate the pooulation mean annual income for people over age 40 in your state. You choose a random sample of such incomes and compute the mean of the sample as

dollars with a standard deviation of 7575.1 dollars. (a) What is the best point estimate, based on the sample, to use for the population mean?

(b) For each of the following sampling scenarios, determine which distribution should be used to calculate the critical value for the

confidence interval for the population mean. (In the table,

refers to a standard normal distribution, and

refers to a costribution.) \table[[Sampling scenario,

,t,Could use elther Z or !,Unclear],[The sample has size 19, and it is from a normally distributed population with an unknown standard deviation.,,,,],[The sample has size 10, and it is from a normally distributed population with a known standard deviation of 7840 .,,,,],[The sample has size 95, and it is from a non-normally distributed population.,,,,]]