# 16.E: Transformations (Exercises)

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

## General Questions

### Q1

When is a log transformation valuable?

### Q2

If the arithmetic mean of $$\log_{10}$$ transformed data were $$3$$, what would be the geometric mean?

### Q3

Using Tukey's ladder of transformation, transform the following data using a $$λ$$ of $$0.5: 9, 16, 25$$

### Q4

What value of $$λ$$ in Tukey's ladder decreases skew the most?

### Q5

What value of $$λ$$ in Tukey's ladder increases skew the most?

## Question from Case Study

### Q6

In the ADHD case study, transform the data in the placebo condition ($$D0$$) with $$λ's$$ of $$0.5$$, $$0$$, $$-0.5$$, and $$-1$$. How does the skew in each of these compare to the skew in the raw data. Which transformation leads to the least skew?

## Contributor

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