Chapter One

1
Chapter One

• Laura and Adrianna

2
Variables and Distributions

•  
• Categorical Variable records which of several
  groups or categories an individual belongs to
•  
• Quantitative Variable takes numerical values
  for which it makes sense to do arithmetic
  operations like adding and averaging
•  
• Distribution tells what values the variable
  takes and how often it takes these values

3
Interpreting Distributions

• Shape The overall shape of the distribution
  is very important. 
•  

Center a value that divides the data so that
about half take larger values and half have
smaller values are on each side of a centering
method.
Spread the extent of the data from smallest to
largest value
Outlier an individual observation that falls
outside the overall pattern of the graph
4
Histograms

• Symmetric the right and left sides of the
  histogram are approximately mirror images of each
  other
•  
• Skewed to the Right the right side of the
  histogram extends much farther out than the left
  side
•  
• Skewed to the Left the left side of the
  histogram extends much farther out than the right
  side

5
Measuring Center

• Trend a long-term upward or downward movement
  over time
•  
• Mean the overall average of the data

6
Standard Deviation

• Variance the average of the squares of the
  deviations of the observations from their mean

7
Quartile Range
8
REVIEW
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