5. Alt to Exp: Correlational and Quasi-Experimental Designs

Correlational Design

A design wherein two different variables are measured or observed to determine whether there is a significant relationship between them.

Response and Outcome variable

Variables measured in correlation

Predictor and Criterion

Variables measured in regression

Predictor

Independent variable in regression

bivariate correlation

another term for simple correlation

simple correlation

a statistical technique used to determine the strength and the direction of the relationship between two variables x and y

Pearson Product-Moment Correlation

also called Pearson’s r.

Karl Pearson

Who devised the Pearson Product-Moment Correlation

Pearson Product-Moment Correlation

It is a measure of strength of a linear association between two variables

direct correlation

another term for positive correlation

inverse correlation

another term for negative correlation

positive correlation

relation between two variables in which high scores on one go with high scores on the other, mediums with mediums, and lows with lows

negative correlation

relation between two variables in which high scores on one go with low scores on the other, medium with mediums, and lows with highs

weak

a correlation coefficient closest to 0 describes a _ correlation

strong

a correlation coefficient closest to 1 or -1 describes a _ correlation

range truncation or restricted range

other terms for Restriction in Range

restriction in range

a situation in which you figure a correlation but only a limited range of the possible values on one of the variables is included in the group studied

Outlier

A data point that does not fit the general trend of your data, but would appear to be a wayward value and not what you would expect compared to the rest of your data points

Quasi-Experimental Design

Often seem like real experiments but they lack one or more of its essential elements, such as manipulation of antecedents and random assignment to treatment condition

Ex Post Factor

A study in which a researcher systematically examines the effects of pre-existing subject characteristic by forming groups based on these naturally occurring differences between subjects.

Nonequivalent Groups Design

A design in which the researcher compares the effect of different treatment conditions on pre existing groups of participant

Longitudinal Design

A method in which the same group of subjects is followed and measured at different points in time. a method that looks for changes across time

Cross-sectional Design

A method in which different groups of subjects who are at different stages are measured at a single point in time. a method that looks for time-related changes

Pre –test/Post test Design

A research design used to assess whether the occurrence of an event alters behavior scores from measurement made before and after the event

Positive Skewed Distribution

Tail extends to the right

Positive Skewed Distribution

mode<median<mean

Positive Skewed Distribution

most data points are on the left

Negative Skewed Distribution

Tail extends to the left

Negative Skewed Distribution

mean<median<mode

Negative Skewed Distribution

most data points are on the right

p<0.5

p-value that shows strong evidence against the null hypothesis