19. Use the IS-LM model to predict the effects of each of the following shocks on income, the interest rate, consumption, and investment. In each case, explain what the Fed should do to keep income at its initial level. a. After the invention of a new high-speed computer chip, many firms decide to upgrade their computer systems. b. A wave of credit-card fraud increases the frequency with which people make c. A best-seller titled Retire Rich convinces the public to increase the percentage of their transactions in cash. income devoted to saving