Post on 28-Dec-2015
Statistics and Research Methods
How to lie, sway, and mislead using statistics
When confronted with any type of data, ask yourself…
o who is included in the sample?► Science – uses random sampling► Pseudoscience – biased selection
o how large is the sample?► Science – >100 if lab, >1K if other ► Pseudoscience – N=1, anecdotal
When confronted with any type of data, ask yourself…
o what data is being presented?► Science – presents all data ► Pseudoscience – only biased
o how is the data presented? ► Science – graphing standards► Pseudoscience – graphs can
lie!
Misleading Graphs
Mean, Median, Mode
1994 Baseball strike about salary:
-Owners argued: typical salary is $1.2 Million
-Players argued: typically salary is $415,000
Which measure of central tendency was each side using?
Mean, Median, and Mode
When confronted with any type of data, ask yourself…
o is this correlation or causation?
► To understand the difference between correlation and causation, we first need to understand how the data is collected…
Research Methods
Correlations
Correlation coefficients range from –1.0 to +1.0
Sign indicates direction ( positive +, or negative - )
Number refers to the strength of the relationship ( higher = stronger )
Experiment
Correlation v. Causation
Depressed Mood Impaired Sleep
Depressed Mood Impaired Sleep
Family Conflict
Depressed Mood Impaired Sleep
Cause?
Cause?
Caus
e?
Cause?
Apply what we have learnedo Quizzes taken from Learning
Module - http://www.psych.ualberta.ca/~ITL/ct/
o Does watching violent TV make children aggressive?o How would you conduct a correlational study
testing this research question? o How would you conduct an experimental study
testing this research questions?
Correlational? or Causational?o A newspaper headline reads, Heavy Drinkers
Get Lower College Grades.
o Your psychology textbook states that some people remember concrete words better than abstract words.
o People who were abused as children are more likely than others to become child abusers
o A health magazine reports that depressed people who continue medication for at least six months are less likely to relapse than people who take medication for less than six months
Horoscope Study
Writing Exercise #2o Horoscope experiment