ILL -LEEKSOV---- - -30 n/alekscgi/x/Isl.exe/10_u-lgNslkasNW8D8A9PVVf0eU6MG8FFOW-3iCXJLnpPFQGg... @ to G Text 3 Ducation 23 of 25 (1 point) | Question Attempt 1 of 1 Time Remaining: 3:42:42 Siara v 13 14 15 16 17 18 19 20 21 22 23 24 You would like to construct a 99%% confidence Interval to estimate the population mean nual 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 40.143 dollars with a standard deviation of !(83 dollars. (a) What is the best point estimate, based on the sample, to use for the population mean? X 5 dollars (b) For each of the following sampling soc arios, determine which distribution should be used to calculate the critical value for the 99% confidence Interval for the population mean. (In the table, Z refers to a standard normal distribution, and I refers to a t distribution.) Sampling scenario Z Could use either Z ort Unclear X 5 The sample has size 19, and it is from a normally distributed O population with a known star ard deviation of 1824 The sample haz size 13, and it is from a normally distributed population with an unknown standard deviation. The sample has size 90, and it is from a non-normally distributed population. Continue Submit Assignment O W AAP