Chapter 4 - Introduction To Hypothesis Testing

Front 1

Hypothesis Testing

Back 1

Procedure for deciding whether the outcome of a study (results for a sample) supports a particular theory or practical innovation (which is thought to apply to a population)

Front 2

Hypothesis

Back 2

Prediction, often based on informal observation, previous research, or theory, that is tested in a research study.

Front 3

Theory

Back 3

Set of principles that attempt to explain one or more facts, relationships, or events; psychologists often derive specific predictions from theories that are then tested in research studies.

Front 4

Research Hypothesis

Back 4

Statement in hypothesis testing about the predicted relation between populations (often a prediction of a difference between population means)

Front 5

Null Hypothesis

Back 5

Statement about a relation between populations that is the opposite of the research hypothesis; statement that in the population there is no difference (or a difference opposite to that predicted) between populations; contrived statement set up to examine whether it can be rejected as part of hypothesis testing.

Front 6

Comparison Distribution

Back 6

Distribution used in hypothesis testing. It represents the population situation if the null hypothesis is true. It is the distribution to which you compare the score based on your sample’s results.

Front 7

Cutoff Sample Score

Back 7

Point in hypothesis testing, on the comparison distribution at which, if reached or exceeded by the sample score, you reject the null hypothesis. Also called critical value.

Front 8

The Hypothesis-Testing Process

Back 8

1. Restate the Question as a Research Hypothesis and a Null Hypothesis About the Populations - EX: M1 > M2, Research Hypothesis. M1 = M2, Null Hypothesis.

2. Determine the Characteristics of the Comparison Distribution - Determine what the Mean and Standard Deviation would be if the Null Hypothesis was true.

3. Determine the Cutoff Sample Score on the Comparison Distribution at which the Null Hypothesis should be Rejected - Cutoff Sample Score can vary, but for Psych 330 0.05% should be universally used.

4. Determine Your Sample’s Score on the Comparison Distribution - Determine where the mean of Testing Distribution falls on your Comparison Distribution.

5. Decide Whether to Reject the Null Hypothesis - Null Hypothesis is false if the mean falls within the Cutoff Sample Score, Null Hypothesis is true if the mean does not fall within the Cutoff Sample Score.

6. Explain it to an 8th Grader - Frazee’s Additional Step

Front 9

Conventional Levels of Significance (p < .05, p < .01)

Back 9

Levels of significance widely used in psychology

Front 10

Statistically Significant

Back 10

Conclusion that the results of a study would be unlikely if in fact the sample studied represents a population that is no different from the population in general; an outcome of hypothesis testing in which the null hypothesis is rejected.

Front 11

Directional Hypothesis

Back 11

Research hypothesis predicting a particular direction of difference between populations - for example, a prediction that the population like the sample studied has a higher mean than the population in general.

Front 12

One-tailed Test

Back 12

Hypothesis-testing procedure for a directional hypothesis; situation in which the region of the comparison distribution in which the null hypothesis would be rejected is all on one-side (tail) of the distribution.

Front 13

Nondirectional Hypothesis

Back 13

Research hypothesis that does not predict a particular direction of difference between the population like the sample studied and the population in general.

Front 14

Two-tailed Test

Back 14

Hypothesis-testing procedure for a nondirectional hypothesis; the situation in which the region of the comparison distribution in which the null hypothesis would be rejected is divided between the two sides (tails) of the distribution.