This presentation is the property of its rightful owner.
1 / 7

# Binomial Effect Size Display PowerPoint PPT Presentation

Binomial Effect Size Display. What is it? How do I prepare it?. What is It?. An interesting way to look at a magnitude of effect estimate. A 2 x 2 contingency table Total N = 200 For each row N = 100 For each column N = 100 Treat the cell entries as conditional percentages.

Binomial Effect Size Display

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

## Binomial Effect Size Display

What is it?

How do I prepare it?

### What is It?

• An interesting way to look at a magnitude of effect estimate.

• A 2 x 2 contingency table

• Total N = 200

• For each row N = 100

• For each column N = 100

• Treat the cell entries as conditional percentages

### Calculating the Cell Entries

• Obtain the r for the effect of interest.

• On one diagonal the cell entries are 100(.5 + r/2)

• On one diagonal the cell entries are 100(.5 - r/2)

### Physicians’ Aspirin Study

• φ2 = .0011

• r = φ = .034

• 100(.5 + r/2) = 100(.5 + .017) = 51.7

• 100(.5 – r/2) = 100(.5 - .017) = 48.3

### Interpretation

• The treatment explains 0.11% of the variance in heart attacks.

• This is equivalent to a treatment that reduces the rate of heart attacks from 51.7% to 48.3%.

• Odds ratios can be revealing too. Here the odds ratio is (189/10,845)/(104/10,933) = 1.83.

• The odds of a heart attack were 1.83 time higher in the placebo group than in the aspirin group.

### Predicting College Grades From SAT (Verbal and Quantitative)

• Multiple R = 0.41

• 100(.5 + r/2) = 100(.5 + .205) = 70.5

• 100(.5 – r/2) = 100(.5 - .205) = 29.5

### Effect from ANOVA

• η2 = .06 (medium-sized effect)

• 100(.5 + r/2) = 100(.5 + .12) = 62

• 100(.5 – r/2) = 100(.5 - .12) = 38