Statistics 1.1.1

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Statistics 1.1.1 Powered By Docstoc
					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
  adding make sense.
 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




          CASA, AP Stats 05-06, Section 1.1.1   7
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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posted:9/28/2012
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