Answer Happy

k. Which of the following would lead a confidence interval for the population mean based on a normal distribution to be narrower (assuming nothing else changes)? (1) Increased sample size (2) Increased confidence level (3) Increased population standard deviation (4) Both (1) and (2) (5) All of the above 1. Consider two discrete random variables with some valid joint probability mass function: X = {the number of credit cards owned by a randomly selected person} Y = {the number of debit cards owned by a randomly selected person} Which of the following statements is TRUE for the correlation coefficient? (1) Suppose the correlation coefficient between X and Y is equal to 0. This implies that the number of credit cards is independent of the number of debit cards owned by a randomly selected person. (2) Suppose the correlation coefficient between X and Y is equal to 0.9. This means that the high usage of debit cards is due to the high usage of credit cards. (3) Suppose the correlation coefficient between X and Y is equal to 0.02. This means that there is almost no relationship between the usage of debit and credit cards for a randomly selected person. (4) Both (1) and (3) (5) All of the above 5