Experimental Design

Specifies the operations or procedures used to measure or manipulate a variable

Correlation Design

is an association between two or more variables.

Within-Groups design

A study in which the different levels of the IV variable are experiaenced by all participants.

Between-Groups Design

A experiment in which participants experience one, and only one of the IV's

What is an advantagbe of a between-groups design?

The different leveles of the IV serve as the distinction between two (or more) groups.

The advantage of a within-groups design?

Compares the same group before and after they experiance the IV.

What is a disadvantage of a between-groups design?

 Participants only experiance ONE variable.

What is a disadvantage of a within-groups design?

Cannot determine causation

Mean

average of a group of scores

Median

The middle score of all scores in a sample

Mode

the most common score of all the scores.

How outliers influence the mean.

The mean is not representative of any one actual score.

How outliers influence the median.

Has almost nothing to do with the actual value of the numbers because it's only the middle

Variance

the average of the sqaured deviations from the mean.

Standard deviation

typical amount that each score varies, or deviates from the mean.

What is variablity important?

Helps describ how much spread there is in a distribution.

What is meant by "a representative sample?"

Participants with characteristics that closely match the characteristics of the whole population

Why is it important to obtain a representative sample?

So that the whole population's view is counted, and not baised on one group.

Why is it important to include sampling error in your answer?

Because the sample dosen't include the total population.

What technique is used to get a representative sample?

Random assignment.

Why z scores are useful.

To compair one thing to another based on how far it is from the mean.

Type I Error

when we reject the null hypothesis, but the null is correct.

Type II Error

When we fail to reject the null, but the null is false.

Describe the central limit theorem.