## Inferences from Two Samples

Definitions

- Dependent Samples
- Samples in which the subjects are paired or matched in some way. Dependent samples
must have the same sample size, but it is possible to have the same sample size without
being dependent.
- Independent Samples
- Samples which are independent when they are not related. Independent samples may
or may not have the same sample size.
- Pooled Estimate of the Variance
- A weighted average of the two sample variances when the variances are equal. The
variances are "close enough" to be considered equal, but not exactly the same, so this
pooled estimate brings the two together to find the average variance.

Table of contents

James Jones