Worksheet 2 1. A researcher is investigating the relationship between the number credit cards owned by a consumer and the number of online purchases made in a week. The joint probability distribution for the number of credit cards owned and number of online purchases made in a week is as follows: Y (number of online purchases in a week) 0 1 2 0.21 0.09 0.09 X (number of credit cards) WNA 0. 11 0.08 0. 16 0.04 0.06 0.16 (a) If a person is randomly selected, what is the expected number of credit cards owned, and the expected number of online purchases made in a week? (b) Find the variance for number of credit cards owned and number of online purchases made in a week. Calculate the covariance between number of credit cards owned and number of online purchases made in a week. Are these two variables statistically independent? Explain your answer. (c) Do these results indicate that the number of online purchases in a week increases with the number of credit cards owned? Explain your