Types of Statistics

1
Chapter 1

• Introduction

2
Types of Statistics

• Descriptive Statistics
• Describe a set of observations (a.k.a., data)
• Examples
• Central Tendency
• Variability
• Shape
• Frequency, Relative Frequency, Cumulative
  Frequency, Relative Cumulative Frequency

3
Types of Statistics

• Inferential Statistics
• Generalize Beyond Observations
• Use a sample to make claims about a population.
• Examples
• Hypothesis test
• Less than 5 chance Rule
• Estimation

4
Numbers

• What does this mean?
• 2
• Answer A position on a scale 2 units away from
  zero.
• It might not even mean that! Could just be a
  category.

5
Types of Scales
Q Order?
Nominal Scale
Q Consistent Difference?
Ordinal Scale
6
Types of Scales
Ordinal Scale
Ratio Scale
7
Types of Scales
Q Order?
Nominal Scale
Q Consistent Difference?
Ordinal Scale
Q True Zero?
Interval Scale
Ratio Scale
8
Types of Scales
Q Order?
Nominal Scale
Qualitative
Q Consistent Difference?
Ordinal Scale
Q True Zero?
Interval Scale
Ratio Scale
9
Types of Scales
Q Order?
Nominal Scale
Qualitative
Q Consistent Difference?
Ordinal Scale
Q True Zero?
Interval Scale
Ratio Scale
Quantitative
10
Types of Scales
Ordinal Scale
Ratio Scale
11
Types of Variables

• Variable
• An entity that can take on different values.
• Its value can vary.

12
Types of Variables

• Independent Variable (IV)
• Manipulated
• Changes in value independent of other factors.
• Set by the experimenter.
• Dependent Variable (DV)
• Measured
• Changes in value depend on changes in the IV

13
Types of Studies

• Correlation
• Measure 2 DVs
• See if they change together.
• Example
• Question Is alcohol use and violence related.
• Query Method Find violent and non-violent people
  and assess their alcohol use.

14
Types of Studies

• Experiment
• Manually change an IV
• See if a change in the DV follows.
• Example
• Question Is alcohol use and violence related.
• Query Method
• Give people different amounts of alcohol
• Measure violence level and see if it changes