Statistics

1
Statistics Research
2
General Background

• Importance of Statistics
• Numbers are powerful
• Understanding research
• Conducting research
• Software
• SPSS
• Excel

3
Variables

• Variable something that can take on more than
  one value
• Independent variable explains or causes
• Dependent variable explained or effect

4
Examples of Variables

• Possible values
• Female, male
• Blue, brown, green
• Fr, soph, jr., sr.
• 6, 19, 25, 70 (years)
• 60, 72, 84 (inches)
• 79, 101, 220 (lbs)
• 1.5, 2.0, 3.0 (secs)
• 500, 600 (scores)
• 40, 50, 60 (scores)

• Example
• Sex
• Eye color
• Class standing
• Age
• Height
• Weight
• Visualization
• SAT-Verbal
• Curiosity

5
Population Sample

• Population the complete collection everyone of
  interest (adults in U.S. students at USF)
• Sample a subset of the population (students at
  USF are a sample of adults in U.S. student in
  this class are a sample of students at USF). We
  usually do research with a sample. Quick and
  cheap. Using the population is too costly.

6
Parameter Statistic

• Parameter a numerical summary of the population
  (average age of students at USF if students at
  USF is the population).
• Statistic a numerical summary of a sample
  (average age of students in this class if
  students at USF is the population).
• Sample statistics serve 2 purposes
• Descriptive
• Inferential

7
Relations among Terms
8
Review Definitions

• Population
• Sample
• Parameter
• Statistic

9
Types of Studies

• Design set of data collection procedures
• Experiment (Experimental study)
• IV manipulated often random assignment
• Correlational study
• IV measured, not manipulated

10
Experiment

• Independent Variable
• schedule
• Dependent Variable
• Rph
• Extraneous Variable(s)
• Sex of experimenter
• marble

11
Another Example

• Brannick wants to know if beer consumption the
  night before an exam is related to exam scores
  the following day. He asks each student taking
  an exam the number of beers they had the night
  before and calculates the total score to see
  relationship.
• Experimental or correlational?
• IV? DV? Extraneous (nuisance)?

12
Definition

• The way in which a study is set up and conducted
  is known as the studys
• Conduct
• Design
• Operation
• Transport

13
Definition

• In an experimental study, the ___________
  variable is usually deliberately manipulated.
• Dependent
• Extraneous
• Independent
• Nuisance

14
Definition

• We want to know about a large group of people,
  but we can only afford to study a small group of
  people. In statistics, the larger group is
  called the
• Focus
• Generalization
• Population
• Sample