# PRINICPLES OF MICROECONOMICS by shuifanglj

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```									Bryon Gaskin
Instructor: Perry Hollowell
Econ 202 IVY TECH FALL 2002

PRINICPLES OF MICROECONOMICS
ECN 202
Unit 3 Assignment

The first two units explored a basic overview of the science of economics. The concept
of scarcity, choice and opportunity cost was introduced. The need for economic systems
was explored by introducing the market system. Both Macroeconomic and
Microeconomic concepts were presented.
The rest of the semester will focus on Microeconomics. Chapters 6, 7 & 8 begin this
journey. Specifically the concept of price elasticity, a measure of consumers’ and
producers’ responses to price changes is emphasized. I cannot stress strongly enough the
need to understand how price elasticity of supply and demand, cross price elasticity, and
income elasticity as it is important in element of economic analysis. Knowledge of the
general nature of production costs is essential to understand how firms make decisions.
Those decisions will depend upon prices (costs) of the resources essential to its
production and the price the product will bring in the market place. Please include the

1. (A) Explain in detail a perfectly elastic demand curve and a perfectly inelastic
demand curve.
When talking about a perfectly elastic demand curve and a perfectly inelastic demand
curve, one must keep in mind that there is a price range that is in reference; because
even such things vital medical supplies, if the price changes so drastically it would
effect inelastic demand. For example, if the cost of Zocor (a cholesterol medication)
has an inelastic demand curve from a price range of \$70 to \$90 for a month’s supply,
if the price were to jump to say \$250 dollars, then the inelastic demand curve would
be no more because less people would being ABLE to buy. Remember for demand,
that not only does the consumer have to WANT to buy it, they also have to be ABLE
A perfectly elastic demand curve is a straight horizontal line can purchase any
amount of the product they want at a given price. In a perfectly elastic demand curve,
the smallest change in price will cause the consumers to change their consumption by
a large amount.
A perfectly inelastic demand curve is represented by a straight vertical line. It
represents that idea that consumers will not change the quantity of goods consumed or
purchased when the price of that good changes.

(B) Price elasticity along a straight-line demand curve refers to what?
Price elasticity along a straight-line demand curve refers to the idea that equal
changes in price means equal changes in quantity. In other words a change x unit
price will mean an equal y change in quantity. So a move from a unit price of
\$10 to \$9 will mean a change in quantity demanded to go from 500 to 475, and a
change in price of \$9 to \$8 will mean a change in quantity from 475 to 450. A \$1
dollar change in price means a 25-unit change in quantity demanded.
Instructor: Perry Hollowell
Econ 202 IVY TECH FALL 2002

10 Points

2.
(A) What are the major determinants of price elasticity of demand?
*The existence of substitutes
*The importance of the product in the consumer’s total budget
*The time period in consideration.
(B) Use these determinants in judging whether demand for each of the following
products is elastic or inelastic.
(a) Oranges Some what elastic because you can substitute other comparable fruits.
(b) Cigarettes Inelastic because there really are not much in the way of substitutes,
and the time frame is short for their purchase.
(c) Winston cigarettes Elastic, because not everyone is brand loyal when it comes to
cigarettes.
(d) Gasoline Inelastic because there are no substitutes.
(e) Diamond bracelets . Elastic because a diamond bracelet purchase is a very
significant percentage on the average consumer’s total budget.
15 Points

3. The income elasticity of demand for movies, dental services, clothing have been
estimated to be +3.4, +1.0, and + 0.5, respectively. Interpret these coefficients.
MOVIES =3.4
DENTAL = 1.0
CLOTHING = 0.5
All of the goods mentioned above are normal goods, because the have
coefficients above zero. In other words, when dealing with normal goods,
income and quantity demanded move in the same direction. A 1% increase in
come means a .5% increase in quantity demanded of clothing, a 1% increase in
quantity demanded for dental services, and 3.4% increase in the quantity
demanded for movies.

15 Points

4. Price discrimination is often used by businesses. Explain the conditions under which
price discrimination is practiced and the economic consequences of price discrimination.
Price discrimination is most common in business where you consumers can
easily be divided into different groups or sectors and those sectors need not
be something that is visual such as old young, rich or poor, but it can be. A
personal example, is two weeks ago I sent a hard drive from work to have data
recovered from it, I asked what the price cost would be and they said that if it
is Hard Drive is being returned to an individual then the price is \$800, if it is
being returned to a business the price is \$1100. The more choice that a
specified group as, the more likely there is to be price discrimination.
Discounts for senior citizens or children to eat or see movies, off peak minute
Instructor: Perry Hollowell
Econ 202 IVY TECH FALL 2002

usage for cell phones, not paying a cover charge for arriving at a bar before
9PM or scheduling your next airfare well in advance and taking a Saturday night
stay, are all examples of price discrimination at work. So why do business use
price discrimination? That is the real question, obliviously there must exist a
motive, and the motive is profit. By tailoring their pricing strategy to
definable groups they are better able to maximize profits. For me buying
items such as coffee is an inelastic demand, if it costs \$.40 cents from the
vending machine or over \$2.00 a Starbucks has no effect on how may cups I
buy. However for senior citizens a \$2.00 cup off coffee would be unthinkable
so might a \$1.00 cup, however if a place offering a cup of coffee for a \$1.00 a
cup to the general public but has very few senior citizens buying coffee at a
\$1.00 cup, then offers coffee at \$.65 a cup for anyone over 65, and increases
the number of cups of coffee sold to people over 65 by 55% then, they have
good reason to practice price discrimination.
15 Points,

5. (A) Why would an ounce of gold be priced higher than an ounce of coffee beans,
even though coffee is generally considered more essential than gold? Explain the
paradox in terms of marginal and total utility.
The paradox of one once of gold being priced higher than one once of coffee
beans given that coffee is considered more essential than gold can be
explained (as in most things in economics) through supply and demand. When
the quantity demanded is limited and in the case of gold finite, but the
quantity demanded is high, the price people will pay for that good will
eventual reach an equilibrium price determined by market forces. If one only
looks at marginal utility to compare the coffee beans and gold then that would
not show the real picture because we would be comparing apples to oranges.
If really want to understand how these goods relate, we must equalize their
satisfaction. This is done by dividing marginal utility by price. In summary,
the marginal utility of coffee beans is low, but so is its price, but it’s total
utility is high. The total utility of all of the coffee beans is very high when
compared to total utility to all of the gold purchased. We affix a higher price
to gold because the supply available is so low when compared with the highly
abundant amount of coffee beans available.

(B) Describe the law of diminishing marginal utility. On what assumptions is this law
based?
The law of diminishing marginal utility is a model for describing how when one
receives an additional good in a specific time period, the level of satisfaction
On what assumptions is this law based?
The law of marginal utility assumes that you can measure happiness. The word
Instructor: Perry Hollowell
Econ 202 IVY TECH FALL 2002

“utility” in “law of diminishing marginal utility” is term used to measure
happiness or just a unit of measure. Also the assumes that at least one
resource is fixed.
10 Points

6. Define overhead, how it can be reduced and how it affects consumers and retailers.
Overhead are the costs that not directly related to the production process.
Overhead can be greatly reduced by technology. For instance, take a company
that is involved in transporting goods from a warehouse to satellite sites
around the country. They then win contracts to supply five times services they
currently supply over the next 2 years. So they go from a firm of 50 trucks to
200 trucks, and a work force of 75 to a work force of 250. What happened? As
they increased the scale of the business they had to hire more people to
phone and email. This cost is not directly related to the production of the
product. However; if the change t a web based computerized system using
barcodes and check points, they could change their administrative costs from
75 to 100 employees, this would decrease the overhead.

15 Points

7. Explain the difference between the short run and long run. What costs do firms
consider in the short run and long run?
10 Points
The biggest difference between the short run and the long run is that the
short run is constrained by the law of diminishing marginal returns and the long
run is not constrained by this law. The reason for this is, is because short run
contains at least one variable that cannot be changed. Whenever one variable
cannot be changed then you will always run into a point in which adding more
input will eventually decrease output. The long run does not have to be
affected this way. In the long run the variable that was unchangeable in the
short can be changed and therefore is not the limiting factor in production.
When all of the resources in firm are changed in the long run, the change
means the firm is operating at a different scale and the firm moves into a short
run period.

What costs do firms consider in the short run and long run?
In the short run, firms are concerned about variable costs, because they
cannot do anything about the fixed costs. In the long run firms are still
interested in the variable costs, because what was once a fixed cost in the
short run can become a variable cost in the long run. In the long run since all
of the costs are variables, there are not diminishing marginal returns, for the
mere fact that all of the resources are variable, it is only when you have at
Instructor: Perry Hollowell
Econ 202 IVY TECH FALL 2002

least one resource that is variable are you restrained by the law of diminishing
marginal returns.

8.     (A) Use the concepts of economies and diseconomies of scale to explain the shape
of a firm’s long-run ATC curve.
First lets look at what three types economies of scale we have. 1st,
economies of scale are situations were the cost of producing a unit good
decreases as the quantity produced increased. 2 nd, constant returns to
scale, this happens when there no change in cost of the each unit
produced as the quantity produced rises. 3rd, diseconomies of scale is a
situation in which the cost of producing each unit increases as the total
quantity produced increases. The long run can be shaped as the normal U
which represents economies of scale, constant returns to scales, and
diseconomies of scale, or it can be a continuously gradual sloping line for
an economy of scale or it can be a flat horizontal line when it is operating
in a constant returns to scale. Regardless of which one it operates as, the
long run ATC curve connects the lowest cost for each level of output
represented by the Short run ATC. Even though the Long Run ATC can be
different shapes, the Short Run ATC curve will always be “U” shaped
because of the law of diminishing marginal returns.

What is the concept of minimum efficient scale?
The concept of minimum efficient scale is that it is the lowest point on the
LRATC. It is the point where cost to make each unit of a product is the
lowest or most efficient.

(B) What bearing can the shape of the long-run ATC curve have on the structure of
an industry?
To explain what bearing the shape of the LRATC curve on a industry structure
lets look at three main shapes. In the first shape if the average total cost
descends rapidly to its minimum point and then rises very quickly there after,
then the there are probably a lot of small firms in the industry. The second
shape would be caused when there is a gradual descend over long range output
until it reaches it’s minimum point, then there are only a few very large firms
in the industry. The final shape is caused when the average total cost drops
very quickly to the minimum cost over the long range of output, then industry
is probably configured of large firms and small firms alike.
10 Points

TOTAL 100 POINTS