Hungry Minds Cliffs Gre_INTRODUCTION TO GRAPHS AND CHARTS

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INTRODUCTION TO GRAPHS
AND CHARTS
Graphs and charts appear in the quantitative section of the exam.
Ability Tested
You will need to understand and derive information from graphs, charts, and ta-
bles. Many of the problems require brief calculations based on the data, so your
mathematical ability is also tested.
Basic Skills Necessary
The mathematics associated with diagrammatic interpretation does not go beyond
high-school level. Your familiarity with a wide range of chart and graph types will
help you feel comfortable with these problems and read the data accurately.
Directions
You are given data represented in chart or graph form. Following each set of data
are questions based on that data. Select the best answer to each question by refer-
ring to the appropriate chart or graph and mark your choice on the screen. Use
only the given or implied information to determine your answer.
Analysis
Remember that you are looking for the best answer, not necessarily the perfect an-
swer. Often, graph questions ask you for an approximate answer; if this happens,
don’t forget to round off numbers to make your work easier.
Use only the information given; never “read into” the information on a graph.
Suggested Approach with Samples
Here are some helpful strategies for extracting accurate information, followed by
some sample graph questions.
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Skim the question and quickly examine the whole graph before starting to
work the problem; this type of prereading will tell you what to look for.
Sometimes the answer to a question is available in supplementary informa-

tion given with a graph (heading, scale factors, legends, and so on); be sure
to read this information.
Look for the obvious: dramatic trends, high points, low points, and so on.
Obvious information often leads directly to an answer.
You may need to scroll the graph to see all the information it contains.
Charts and Tables
Charts and tables are often used to give an organized picture of information, or
data. Make sure that you understand the information that is given. Column head-
ings and line items give you the important information. These titles give the num-
bers meaning.
First, pay special attention to what information is given in the chart. For example, the
following chart shows the number of “Burger Sales for the Week of August 8−14.”
The days of the week are given along the left side of the chart. The number of
hamburgers for each day is given in one column and the number of cheeseburgers in
the other column.
Samples
Questions 1–3 refer to the following chart.
BURGER SALES FOR THE WEEK OF AUGUST 8−14
Day Hamburgers Cheeseburgers
Sunday 120 92
Monday 85 80
Tuesday 77 70
Wednesday 74 71
Thursday 75 72
Friday 91 88
Saturday 111 112
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1.
On which day were the most burgers sold (hamburgers and cheeseburgers)?
A. Sunday

B. Monday
C. Friday
D. Saturday
E. Tuesday
D. To answer this question, you must understand the chart and do some simple
computation. Working from the answers is probably the easiest method.
A. Sunday 120 + 92 = 212
B. Monday 85 + 80 = 165
C. Friday 91 + 88 = 179
D. Saturday 111 + 112 = 223
E. Tuesday 77 + 70 = 147
Another method is to approximate the answers.
2.
On how many days were more hamburgers sold than cheeseburgers?
A. 7
B. 6
C. 5
D. 4
E. 3
B. To answer this question, you must compare the sales for each day. Hamburgers
outsold cheeseburgers every day except Saturday.
3.
If the pattern of sales continues,
A. the weekend days will have the fewest number of burger sales next
week.
B. the cheeseburgers will outsell hamburgers next week.
C. generally, when hamburger sales go up, cheeseburger sales will go up.
D. hamburgers will be less expensive than cheeseburgers.
E. more customers will buy hamburgers than cheeseburgers next Saturday.
C. To answer this question, you must notice one of the trends. Most days that

hamburger sales go up, cheeseburger sales go up (with the exception of Saturday
to Sunday).
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Introduction to Graphs and Charts
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Graphs
Information may be displayed in many ways. The three basic types of graphs you
should know are bar graphs, line graphs, and pie graphs (or pie charts).
Bar Graphs
Bar graphs convert the information in a chart into separate bars or columns. Some
graphs list numbers along one edge and places, dates, people, or things (individual
categories) along another edge. Always try to determine the relationship between
the columns in a graph or chart.
Question 4 refers to the following graph.
4.
Candidate 1 has approximately how many more delegates committed than
does Candidate 2?
A. 150
B. 200
C. 250
D. 400
E. 450
C. To understand this question, you must be able to read the bar graph and make
comparisons. Notice that the graph shows the “Number of Delegates Committed
to Each Candidate,” with the numbers given along the bottom of the graph in
200 400
Delegates
Number of Delegates Committed to Each Candidate
Candidate 1
Candidate 2

Candidate 3
Candidate 4
600 800
0
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increases of 200. The names are listed along the left side. Candidate 1 has approx-
imately 800 delegates (possibly a few more). The bar graph for Candidate 2 stops
about three quarters of the way between 400 and 600. Now, consider that halfway
between 400 and 600 would be 500. So Candidate 2 has about 550.
800 − 550 = 250
Samples
Questions 5 – 7 refer to the following graph.
5.
The 1994–96 gross receipts of Monster Burger exceeded those of Pizza in a
Pot by approximately how much?
A. 0.2 million
B. 2 million
C. 8.2 million
D. 8.4 million
E. 17 million
B. In this graph, there are multiple bars representing each fast-food category; each
single bar stands for the receipts from a single year.
Gross Receipts of Several Fast-Food Restaurants
1994-1996
3.5
3.0
2.5
2.0

1.5
1.0
0.5
0.0
1994 1995
Monster
Burger
Gross Receipts Millions
1996
1994 1995
Cruncho
Chicken
1996
Pizza in a
Pot
1994 1995
1996
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Introduction to Graph and Charts
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You may be tempted to write out the numbers as you do your arithmetic (3.5 mil-
lion = 3,5000,000). This step is unnecessary, as it often is on graphs that use large
numbers. Because all measurements are in millions, adding zeros doesn’t add pre-
cision to the numbers.
Referring to the Monster Burger bars, you see that gross receipts are as follows:
1994 = 2.5, 1995 = 2.5, 1996 = 3.4 (if you have trouble seeing how the bars line
up with the numbers, you may want to use a piece of scratch paper against the
screen as a straightedge to determine a number like this last one). Totaling the re-
ceipts for all three years, you get 8.4.
Referring to the Pizza In A Pot bars, you see that gross receipts are as follows:

1994 = 1, 1995 = 2.1, 1996 = 3 (don’t designate numbers beyond the nearest
tenth, because the graph numbers and the answer choices prescribe no greater ac-
curacy than this). Totaling the receipts for all three years, you get 6.1.
So, Monster Burger exceeds Pizza In A Pot by 2.3 million. The answer that best
approximates this figure is B.
6.
From 1995 to 1996, the percent increases in receipts for Pizza In A Pot
exceeded the percent increase for Monster Burger by approximately how
much?
A. 0%
B. 2%
C. 10%
D. 15%
E. 43%
C. Graph questions on the GRE may ask you to calculate percent increase or per-
cent decrease. The formula for figuring either of these is the same:
()startingamount follows the word
amount of thechange
from
In this case, you may first calculate the percent increase for Monster Burger.
Gross receipts in 1995 = 2.5
Gross receipts in 1996 = 3.4
Amount of the change = 0.9
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The 1995 amount is the “starting” or “from” amount.
""
.
.

.%
starting amount
amount of change
25
09
036 36== =
Percent increase for Pizza In A Pot:
Gross receipts in 1995 = 2.1
Gross receipts in 1996 = 3
Amount of the change = 0.9
""
.
.
.%
starting amount
amount of change
21
09
0 428 43ÜÜ=
So, Pizza In A Pot exceeds Monster Burger by 7% (43% − 36%). The answer that
best approximates this figure is C.
7.
The 1996 decline in Cruncho Chicken’s receipts may be attributed to
A. an increase in the popularity of burgers.
B. an increase in the popularity of pizza.
C. a decrease in the demand for chicken.
D. predictable slump attributable to the increase in terrorist activity.
E. It cannot be determined from the information given.
E. Never use information that you know is not given. In this case, the multiple
factors that could cause a decline in receipts are not represented by the graph. All

choices except E require that you speculate beyond the information given.
Line Graphs
Line graphs convert data into points on a grid. These points are then connected to
show a relationship between the items, dates, times, and so on. Notice the slopes
of lines connecting the points. These lines will show increases and decreases. The
sharper the slope upward, the greater the increase. The sharper the slope down-
ward, the greater the decrease. Line graphs can show trends, or changes, in data
over a period of time.
Samples
Questions 8–9 refer to the following graph.
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8.
In which of the following years were there about 500,000 American Indians?
A. 1940
B. 1950
C. 1960
D. 1970
E. 1975
C. To answer this question, you must be able to read the graph. The information
along the left side of the graph shows the number of Indians in increases of
100,000. The bottom of the graph shows the years from 1910 to 1980. Notice that
in 1960 there were about 500,000 American Indians in the United States. Using
the edge of your answer sheet like a ruler helps you see that the dot in the 1960
column lines up with 500,000 on the left.
9.
During which of the following time periods was there a decrease in the
American Indian population?
A. 1910 to 1920

B. 1920 to 1930
C. 1930 to 1940
D. 1960 to 1970
E. 1970 to 1980
American Indian Population in the United States from 1910 to 1980
700,000
800,000
600,000
500,000
400,000
300,000
200,000
100,000
0
1910 1920 1930 1940 1950
Years
1960 1970 1980
Population
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