Flashcards in Chapter 8 - Hypothesis Testing (Two-Sample) Deck (10):

1

## Two-sample hypothesis testing

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- in a two-sample hypothesis-testing problem, the underlying parameters of two different populations, neither of whose values are known, are compared

- different tests are available, depending on study design

2

## Longitudinal or follow-up study

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- the same group of people is followed over time

- also, this represents a paired-sample design because each person is used as his or her own control

3

## Cross-sectional study

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- the participants are seen at only one point in time

- this study represents an independent sample design because two completely different groups of people are being compared

- a cross-sectional study is also less expensive than a follow-up study

4

## Types of two-sample data

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- paired samples

- independent samples

5

## Paired samples

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- when each data point in the first sample is matched and is related to a unique data point in the second sample

- may represent two sets of measurements on the same people

- or, on different people who are chosen on an individual basis using matching criteria

6

## Independent samples

### - when the data points in one sample are unrelated to the data points in the second sample

7

## Two-sample t-test for independent samples

### - the two-sample t-test for independent samples is used to test hypotheses of independent samples

8

## F distribution

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- not a symmetric distribution

- positively skewed

- family of distributions that depend on degrees of freedom

9

## Two-sample t-test for independent samples with unequal variances

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- since variances are unequal, we shouldn’t use a pooled estimate of variance

- instead, the traditional estimates for variances are used

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