A change in one variable may be associated with a change in another variable.
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What is point biserial correlation?
When one of the two variables is DICHOTOMOUS (yes/no) (male/female) (jeff/russ)
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What is partial correlation?
Measuring two variables whilst controlling for the effect that a third variable has on them BOTH.
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What is semi partial correlation?
Measures the relationship between two variables, controlling for the effect that a 3rd variable has on 1 of the variables in the correlation.
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What is a comparative correlational design?
Compares the scores of a group of participants with that of another group, usually using the mean scores as a point of comparison.
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What is a correlational research design?
Used to describe the relationship between or among variables.
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What is correlation coefficient r?
A standardised index that describes the direction and strength/magnitude/size of the relationship between X and Y.
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What score indicates no relationship in correlation coefficient?
0
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What scores indicate a small, medium or large effect for correlation coefficient?
+.1 (small), =+.3 (medium) +.5= large
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The coefficient of determination r is what and represents what?
R squared - the proportion of variance in one variable shared by another. It is a measure of how well the regression line fits the data.
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what does the R squared percentage represent?
The amount of variance that is explained by the linear relationship between X and Y.
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Scatter plots provide a....
Graphical representation between two variables (X and Y)
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What is covariance?
Based on the idea that if two groups are related, then their means will change also and so will their deviations. therefore, covariance is the standard amount of cross product deviations.
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In Correlation df is?
N- 2.
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Once we have calculated the value of r, what must we do?
To see if it is statistically significant. The obtained value of r must be larger than the predicted value of r to reject H0.
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Correlation coefficient is a standardised version of what?
Covariance.
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What is the problem with covariance and how can we address this?
It depends upon the units of measurement, so we divide by the standard deviations of X and Y.
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Other cards in this set
Card 2
Front
What is a correlational relationship?
Back
A change in one variable may be associated with a change in another variable.
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