Unit 5—Aggregate Models
Download
Report
Transcript Unit 5—Aggregate Models
Unit 5—Aggregate
Models
Chapters 9, 10 and focus on 11
Time Period: 3 weeks
Graphs: 6
Chapter 9—Building the
Aggregate Expenditures
Model
Aggregate means TOTAL
(aggregate expenditure means total
spending)
Consumption and Saving
What can a person do with DI?
What is not spent is called savings
DI – C = S
LOOK AT THE GRAPH ON PAGE 160
C & DI Graph
The reference line is a 45° line
Green dots = C
When the green dot falls short of the reference
line, savings has occurred
Each point is equidistant from the axes
C = DI
Again, DI – C = S
As DI increases both C and S increase
Direct relationship to the level of income
Household C most of their DI
C Schedule
Page 161 shows a hypothetical C schedule
Households spend a larger proportion of a small
income than of a large income
See graph on Page 162
C Schedule Graph
45° reference line
Shows C and S
Shows DISSAVINGS = occurs at low levels of
income where C exceeds DI & people must borrow
Average Propensities to C & S
Measures the average C (APC) or S (APS) at
any level of disposable income
APC = C / DI
APS = S / DI
C% and S% as DI
APC + APS = 1
Marginal Propensities to C & S
(marginal means extra)
Proportion of any change in income C is called MPC
or income S is called MPS
MPC = ∆ C / ∆ DI
MPS = ∆ S / ∆ DI
MPC + MPS = 1
The only choice people have is to C or to S. An additional
dollar in income must result in a change in C and/or a
change in S.
Practice worksheet
Investment
Spending on new plants, capital equipment,
machinery, construction, etc.
Investment decision weighs mb & mc
The expected rate of return = mb
The interest rate = mc
Expected Rate of Return
Found by comparing the expected economic
profit (total revenue minus total cost) to cost of
investment to get expected rate of return
Example in text (page 166)
Woodworker wants to buy equipment for $1,000.
He expects a $100 profit. The expected rate of
return in 10%. In order to make a profit, the
woodworker would not want to pay more than
10% interest on the investment.
The Real Interest Rate
The real interest rate, i, is the cost of the
investment
Real interest rate = nominal rate - inflation
Interest rate is either the cost of borrowed
funds or the cost of investing your own funds,
which is income forgone.
If i exceeds the expected rate of return, r, the
investment should not be made
Shifts in the Investment Demand
Curve—IDC or DIgC
Movement occurs with a change in the interest
rate
Shifts occur due to these determinates:
1. acquisition, maintenance and operating costs
When cost falls, the r from prospective investment
project rises, shifts the IDC to the right
Higher electricity costs = shift to the left
2. business taxes
in taxes = shift to the left
Shifts Continued
3. technological change
Development stimulates investment
(shifts to the right)
4. stock of capital goods on hand
When firms are overstocked, the r declines
(shifts to the left)
There is little incentive to invest in new capital
when there is excess production
When firms are under stocked, the r increases
(shifts to the right)
Shifts continued again . . .
5. Expectations
Optimistic about future sales, the curve will
shift to the right
Pessimistic outlook = shift to the left
Instability of Investment
1. capital goods are durable so spending can
be postponed
2. innovation occurs irregularly
3. profits vary considerably
4. expectations can be easily changed
Classwork! Yeah!
Page 179
Number 2
Number 3
Number 4
Number 5—complete the table only—and part
b (refer to table 9.1)
Number 6
Due today -- or homework if not
finished
Equilibrium GDP
Equilibrium level of GDP is the level at which
the total quantity of goods produced (GDP) =
the total quantity of goods purchased
GDP = C + Ig (in a closed economy)
Savings and investment are equal
Savings represents a “leakage” from spending
and causes C to be less than GDP
Table 9.4
See table on page 173
See line 8, GDP is $510 billion
C + Ig = 500 billion (disequilibrium)
Businesses have $10 billion of unplanned
inventory investment on top of what was
already planned
Unplanned portion is a business expenditure
Table 9.4
See line 5, GDP = $450 billion
Consumer spending is $435 billion
$20 billion is planned investment
Businesses have experienced a $5 billion
unplanned decline in inventory because of
unexpected sales
Self Assessment
See graph on page 175
Quick quiz on page 175—work with a partner
or on your own for your own assessment of
understanding
Says Vs Keynes
Read page 177
Do question 16 on page 180—this will be
turned in. You need to actually draw a PPF
and label efficiency for both men.