Please enable JavaScript.
Coggle requires JavaScript to display documents.
Correlation and shared variance (Correlation: A measure of association…
Correlation and shared variance
Correlation: A measure of association between two
numerical variables.
Positive
Negative
Direction of Association
0 correlation
no relationship
between variables
Pearson's correlation coefficient
Always between +1.00 and -1.00
Strength of Linear Association
95% confidence intervals of correlations
Correlation matrix
Correlation & causality
Correlation output
#
Be aware of correlation claims
Some things may look like they are connected but they are
not
Outliners
Non-linear relationships
effect size
#
calculate r 2 (i.e. r x r)
r 2 x 100: Percentage of shared variance
Relationships: we wish to find out if two variables are related to each other and how closely they are related
False casual relationship
Related?
Measure
Pearson’s Sample Correlation Coefficient, r
Graphing
Scatterplot (scatter diagram)
Perfect positive
Perfect negative
Interrelations
Curvilinear
Check data visually
Ordinal data use Spearman's
Spearman's rho may be used instead of Pearson's r (if 3 conditions)
Spearman's rho is computationally identical
to Pearson's r
interpreted in the same way as Pearson’s r
What to use?
Pearson’s Product Moment Correlation
Interval/Ratio level variables
Interval/Ratio and dichotomous variables
Spearman’s Rho
Very skewed Non-normal distributions
Ordinal variables