Hypothesis Testing

1
Hypothesis Testing

• The logic of hypothesis testing
• An example The normal deviate test
• Another example The Sign Test

2
Inferential Statistics

• Hypothesis testing and parameter estimation
• Marijuana and reaction time
• Grape Kool-Aid and IQ
• The repeated measures designs
• Order and sequencing issues Randomize

3
Stated as steps

• 1. State the hypotheses
• 2. Set the criteria for belief
• 3. Collect and analyze the data
• 4. Make a decision

4
Hypotheses and decisions

• The null hypothesis
• The alternative hypothesis
• Decision criteria
• If the probability of an experiments outcome
  occurring by chance is less than a, reject the
  null hypothesis.

5
Technical issues

• Type I error Rejecting a true null hypothesis
• Type II error Retaining a false null hypothesis
• Controlling errors Alpha and N
• Tailedness One and two tailed tests

6
The normal deviate test

• Z for samples
• Z M m
• sM

7
Effect size

• Cohens d difference between means
• standard deviation
• Or d M m
• s

8
Using the binomial distribution to make
decisions The sign test

• Convert repeated measures comparisons to pluses
  and minuses
• Discard any ties
• Find the probability for the number of pluses
  from the binomial distribution, and for the more
  extreme numbers of pluses.