Psychstats Lesson 6

Hypothesis-Testing

a statistical method that uses sample data to evaluate hypothesis about a population

• procedure for 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)

Hypothesis

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

Theory

• set of principles that attempt to explain one or more facts, relationships, or events

Hypothesis Testing Process

1\. State the Hypothesis

2\. Set the Criteria for a Decision

3\. Determine the Characteristics of the Comparison Distribution and the Cutoff Sample Score.

4\. Collect data and compute sample statistics.

5\. Make a Decision.

Null Hypothesis

states that, in the general population, there is no change, no difference, or no relationship

Alternative Hypothesis

also known as the research hypothesis, states that there is a change, a difference, or a relationship for the general population

1\. State the Hypothesis.

Restate the research question as a Null Hypothesis and an Alternative Hypothesis about the Populations.

2\. Set the Criteria for a Decision.

Find the boundaries that separate the high-probability samples from the low probability samples.

Level of Significance (α)

also known as alpha level, is a probability value that is used to define the concept of “very unlikely” in a hypothesis test

• α = 0.05, α = 0.01

Comparison Distribution

is testing which represents the population situation if the null hypothesis is true

Cutoff Sample Score

• also known as critical value, is a point in hypothesis- testing, on the comparison distribution, at which, if reached or exceeded by the sample score, you reject the H

Critical Region

• composed of the extreme sample scores/values that are very unlikely to be obtained if the null hypothesis is true

Statistical Significance

a result is said to be significant or statistically significant if it is very unlikely to occur when the null hypothesis is true

Directional Hypothesis

research hypothesis predicting a particular direction of difference between populations

One-tailed Test

\- is a situation in which the region of the comparison distribution in which the H0 would be rejected is all on one side (tail) of the distribution

Nondirectional Hypothesis

research hypothesis that does not predict a particular direction of difference between the population

two-tailed test

situation in which the region of comparison distribution in which the null hypothesis would be rejected is divide in two sides (tails) of the distribution