# Statistics 1.1.1

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Section 1.1
Part 1
AP Statistics
CASA

CASA, AP Stats 05-06, Section 1.1.1   1
We study statistics because…
 … anecdotal evidence is not reliable.
 … we don’t wish to be lied to.
 … spotting trends helps us make good
decisions
 Simply, we study statistics because we
want to make sense of the world.

CASA, AP Stats 05-06, Section 1.1.1   2
Vocabulary
 Individuals – objects in a data set.
Sometimes referred to as x1, x2, x3, etc.
 Variable – any characteristic of an
individual
 Thinking of the individuals in this room,
what might some of their characteristics?

CASA, AP Stats 05-06, Section 1.1.1   3
Categorical vs. Quantitative
 Categorical variables places individuals in
one of several groups.
 Quantitative variable takes numerical
values for which arithmetic operations like
 Of the variables describing the members
of the class, which are categorical and
which are quantitative?

CASA, AP Stats 05-06, Section 1.1.1   4
Distribution
 “The distribution of a variable tells us what
values the variable takes and how often it
takes these values.”
 How distributions differ between
categorical and quantitative variables?

CASA, AP Stats 05-06, Section 1.1.1   5
Bar and Pie Charts
   Both show relative frequencies of
categorical values in a data set.

CASA, AP Stats 05-06, Section 1.1.1   6
Problems with Pie Charts

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Attributes of a “good” chart
1999 Soft Drink Sales

   Title                          50

45

   Axis Labels                    40

35

   Consistent Scale               30

Percent
25

20

15

10

5

0
Coca-Cola   Pepsi Co.   Dr. Pepper/7-   Cott Corp.   National   Royal Crown   Other
Co.                       Up                      Beverage
Company

CASA, AP Stats 05-06, Section 1.1.1                                                                         8
Assignment
   Exercises 1.1 – 1.6, Practice of Statistics

CASA, AP Stats 05-06, Section 1.1.1   9

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