After completing this chapter you should be able to:
- Explain how the concept of a signal-to-noise ratio applies to t tests.
- Discuss the relationship between degrees of freedom (df) and p values.
- Describe how a t test on independent samples is computed.
- Explain how the effect size r is estimated directly from t.
- Define Cohen's d and Hedges's g.
- Discuss why t is said to be the product of the effect size and the study size.
- Describe how one can maximize t.
- Describe how a t test on related samples is computed.
- Identify the statistical assumptions of the t test.