Regression Analysis Flashcards Preview

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Flashcards in Regression Analysis Deck (14):

What is Regression?

Regression Analysis will provide you with an equation for a graph so that you can make predictions about your data.

It is used in stats to find trends in data. It is the best guess at using a set of data to make some kind of prediction.

Quantifies the degree of impact one variable has on another, thus enabling a prediction.

Can use it to predict someone's score on some variable.


What does Regression give you the ability to do?

It gives you the ability to predict things. If a relationship is linear then should be able to predict one thing from another.


What is Pearson's Correlation?

The strength of relationship between two variables. It is the extent to which X varies from Y. Denoted by R or r. Goes between -1 or+1. A coefficient of +1 indicates two variables are positively correlated.


What goes on the X axis and what goes on the Y axis?

Variables which "varies" (Independent Variable) on the X axis.

Dependent Variables (DV) go on the Y axis.


What line is the Predictor Variable?
What line is the Criterion Variable?

Your predictor Variable is X, the Independent Variable.
Your criterion Variable is Y, the Dependent Variable.


What is the Predictor Variable?

Similar in meaning to the independent variable, but used in regression and in non-experimental studies.

Your predictor Variable is X, the Independent Variable.

The Independent variable is a variable that is not affected by anything that you, the researcher, does. Usually plotted on the x-axis.


What is the Criterion Variable?

Criterion variable: another name for a dependent variable, when the variable is used in non-experimental situations.

The outcome of an experiment. As you change the independent variable, you watch what happens to the dependent variable.


What are Cohen's guidelines of Magnitude?

It is an effect size. A Quantitative measure of the magnitude of a phenomenon.

Cohen’s guidelines of magnitude (1988) • .1 -.29 = small • .3 -.49 = medium • .5 -1 = large


How do you interpret the Regression line/Line of best fit and what is it?

You want to see how closely all the data points lie along the line of best fit.

The line of best fit -the regression line enables prediction.

A regression line is the “best fit” line for your data. You basically draw a line that best represents the data points. It’s like an average of where all the points line up. In linear regression, the regression line is a perfectly straight line:


What is the basic equation of a line and what is it used for?

y’ = a + bx.

A regression equation is used in stats to find out what relationship, if any, exists between sets of data.

Regression equations can help you figure out if your data can be fit to an equation. This is extremely useful if you want to make predictions from your data–either future predictions or indications of past behavior. For example, you might want to know what your savings are going to be worth in the future. Or, you might want to predict how long it can take to recover from an illness.


What is a Scatteplot?

A graph depicting the nature of association between two variables in graphical form.


What can be Pearson's r be badly affected by?

Can be badly affected by data which either have outliers or specific underlying functions which are not linear eg curvilinear (a smooth curve of any shape). A Scatterplot will tell you what the pattern of the data is and whether there are any serious outliers or non linear functions.


What is Simple Regression?

Linear regression is a way to model the relationship between two variables. Multiple regression has more than 2 variables.


What does Std. Residual mean? (Note this is in Casewise Diagnostics in SPSS output)

Std. Residual identifies how many standard errors of prediction the selected data point is away from the regression line.

Tells you how far way something deviates from the regression line.