For each of the following, decide whether the proper inference is a prediction interval for y or

Question:

For each of the following, decide whether the proper inference is a prediction interval for y or a confidence interval for E (y):
a. A jeweler wants to predict the selling price of a diamond stone on the basis of its size (number of carats).
b. A psychologist wants to estimate the average IQ of all patients who have a certain income level.