用IS-LM模型预测下列冲击对收入、利率、消费和投资的影响。在每种情况下。解释美联储为了把收入维持在初始水平上应该采取什么措施?
a．在发明一种新的高速电脑芯片之后，许多企业决定把自己的电脑系统升级。
b．信用卡诈骗浪潮提高了人们用现金进行交易的频率。
c．名为《退休富人》(Retire Rich)的畅销书说服公众增加收入中用于储蓄的百分比。
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 tile 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 transactions in cash.
c．A best-seller titled Retire Rich convinces the public to increase the percentage of their income devoted to saving.