# 19.6: Effect Size (Exercises)

• • Contributed by David Lane
• Associate Professor (Psychology, Statistics, and Management) at Rice University

## General Questions

### Q1

If the probability of a disease is $$0.34$$ without treatment and $$0.22$$ with treatment then what is the

1. Absolute risk reduction
2. Relative risk reduction
3. Odds ratio
4. Number needed to treat

### Q2

When is it meaningful to compute the proportional difference between means?

### Q3

The mean for an experimental group is $$12$$, the mean for the control group were $$8$$, the $$MSE$$ from the ANOVA is $$16$$, and $$N$$, the number of observations is $$20$$, compute $$g$$ and $$d$$.

### Q4

Two experiments investigated the same variables but one of the experiment had subject who differed greatly from each other where as the subjects in the other experiment were relatively homogeneous. Which experiment would likely have the larger value of $$g$$?

### Q5

Why is $$ω^2$$ preferable to $$η^2$$?

### Q6

What is the difference between $$η^2$$ and partial $$η^2$$?

## Questions from Case Studies

The following questions are from the Teacher Ratings case study.

### Q7

What are the values of $$d$$ and $$g$$?

### Q8

What are the values of $$ω^2$$ and $$η^2$$?

The following question is from the Smiles and Leniency case study.

### Q9

What are the values of $$ω^2$$ and $$η^2$$?

The following question is from the Obesity and Bias case study.

### Q10

For compute $$ω^2$$ and partial $$ω^2$$for the effect of "Weight" in a "Weight x Relatedness" ANOVA.

## Contributor

• Online Statistics Education: A Multimedia Course of Study (http://onlinestatbook.com/). Project Leader: David M. Lane, Rice University.