Question 1

What does economic equilibrium mean in terms of planned spending and output?

Accepted Answer

Economic equilibrium occurs when planned aggregate expenditure equals aggregate output. At this point, firms sell exactly what they plan to produce, and everything manufactured is purchased. There are no unexpected inventory changes, so businesses have no reason to adjust production levels.

Question 2

How does the planned expenditure curve show the relationship between income and spending?

Accepted Answer

The planned expenditure curve combines consumption and fixed investment, sloping upward to demonstrate that planned spending increases as aggregate output rises. This reflects the positive relationship between income consumption and saving, where households spend more as their income grows while maintaining some baseline consumption even at low income levels.

Question 3

What role does the forty-five-degree line play in finding economic equilibrium?

Accepted Answer

The forty-five-degree line serves as a reference for equilibrium, representing all points where aggregate output exactly equals planned expenditure. The intersection of this line with the planned expenditure curve identifies the equilibrium level of output, where the economy is in balance and production matches planned spending.

Question 4

What happens to inventory and production when planned spending exceeds output?

Accepted Answer

When people plan to spend more than what is being produced, goods sell out quickly and inventory depletes. Firms respond by increasing output to keep up with demand, adjusting production upward until planned spending and output align again at equilibrium.

Question 5

How does inventory buildup signal firms to change production?

Accepted Answer

When production exceeds planned spending, businesses accumulate excess inventory. This buildup signals firms that demand is lower than supply, prompting them to slow down production. This adjustment mechanism helps restore balance between what firms produce and what consumers and businesses plan to spend.

Question 6

Why does consumption increase while investment remains fixed in the planned expenditure model?

Accepted Answer

Consumption grows as people earn more income because households spend a larger portion of additional earnings. Investment, however, is typically assumed to stay constant across all income levels in this model. Together, these components form planned aggregate expenditure, which rises with output due to the consumption component's income sensitivity.

Question 7

At what output level does equilibrium occur in the example presented?

Accepted Answer

Equilibrium is achieved at an aggregate output level of five hundred dollars, where the planned expenditure curve intersects the forty-five-degree line. At this point, planned spending exactly matches production, firms have no unintended inventory changes, and the economy operates in balance without pressure to adjust output.

均衡：计划总支出与总产出