Make one graph that answers the following
question: What percent of all students in 2000
were Political Science majors and what percent
of all students in 2004 were Political Science
majors?
Make one graph to answer the following question:
What percent of all students in 2000 were
Biology majors and what percent were Political
Science majors?
http://www.washingtonpost.com/blogs/ezra
-klein/wp/2012/09/12/chicago-teachersmake-more-than-the-national-average/
http://www.cepr.net/beat-the-press/
In Chicago in the year 2000, there were
approximately 1.053 million African Americans,
907 thousand whites (non-Hispanic), 754
thousand Hispanics, and 181 thousand others
(other races or two or more races). What
percentage of Chicagoans in 2000 were of
Hispanic origin?
Total  1.053  .907  .754  .181  2.895million
part
.754

 .26 or 26%
whole 2.895
In 1994, Zaire’s per capita GNP was $125 (70%
lower than it was in 1958). What was Zaire’s per
capita GNP in 1958?
What people want to do:
$125*(1  .7)  $212.5
Notice, though,
x *(1  .7)  $125
$212.5*(1  .7)  $63.75
x *(1  .7)  $125
Same as:
$125  x
 .7
x
Multiply both sides
by x:
Add x to both sides:
Factor out an x:
$125  x *(.3)
$125  x  .7 x
$125  x  .7 x
$125  x *(1  .7)
x
$125
 $416.67  x
.3
Let’s say you have $100 and you increase this by
5% to get to…
$100*(1+.05) = $105
If you decrease $105 by 5% you get:
$105*(1-.05) =$99.75
What is the overall percentage change?
Started with $100
Ended with $99.75
$99.75  $100
$100
 .0025 or .25%
This dog costume is on
sale for 40% off the
retail price. The retail
price is $40.00. If you
have a coupon, you can
receive an additional
20% off the sale price.
What are the overall
percentage savings?
The sale price:
$40*(1-.4) = $24
Determine the final
price with coupon:
$24*(1-.2) = $19.20
The overall percentage change??
New Value - Reference Value
Reference Value
($19.20  $40)
 .52 or 52%
$40
Not 60%
45.00
40.00
$40.00 x .40 = $16.00
35.00
$40.00 x.52 = $20.80
30.00
25.00
$24.00 x.20 = $4.80
20.00
$40.00 - $16.00 = $24.00
15.00
$24.00 - $4.80 = $19.20
10.00
$40.00 - $20.80 = $19.20
5.00
0.00
Retail Price
Sale Price
Price
Final Price with
Coupon
Amount Saved
Overall Percentage
Change
The absolute quantity is a measure of the
absolute occurrence of the variable.
The relative quantity is the absolute quantity
divided by some other quantity.
Three kinds of relative quantities…
Percentages
Fractions or percents are used when comparing
part to total of the same type of variable.
(example: percent of adults with HIV)
Sorting
Autosum
Change to percent / decimal
What percent of all students
are English students in 2000
and 2004?
2000: =219/905 = 24.2%
2004: = 297/1291 = 23.0%
English majors as a percent of the total
students in 2000 and 2004
24.4%
24.2%
DePaul University
Fact File
24.0%
23.8%
23.6%
23.4%
23.2%
23.0%
22.8%
22.6%
22.4%
2000
2004
DePaul Majors in 2000 and
2004
Area
Biology
2000
239
2004
351
English
219
297
International
Studies
Mathematics
Political Science
Total
137
56
254
905
148
49
446
1291
Rates
Rates are used to compare different types of
variables (example: tickets per person, miles per
hour, or crimes per 1000 people)
Ratios
Ratios are used to compare the same type of
variable from two sources.
California’s population is 33,872,000 and Oregon’s
population is 3,421,000. Clearly CA’s population
is larger but how many times larger?
33,872,000/3,421,000 = 9.90
The moon is 383 thousand kilometers away
from earth. The sun is 149 million
kilometers away. How many times further
away is the sun than the moon?
Absolute or Relative?
I have 16 cheeseburgers.
I have 100% more cheeseburgers than you.
I have 2 times as many cheeseburgers as you.
You have 8 cheeseburgers.
I eat 3 cheeseburgers per hour.
Absolute or Relative?
I have 16 cheeseburgers. Absolute
I have 100% more cheeseburgers than you. Relative
I have 2 times as many cheeseburgers as you.
Relative
You have 8 cheeseburgers. Absolute
I eat 3 cheeseburgers per hour. Relative