Key Terms Flashcards
What is sums of squares?
the sum of the squared deviations of a set of values from the mean
What do we use sums of squares for?
to determine how spread apart the scores are in a data set
What is sums of squares total?
how spread out scores are from the mean of all the scores
What is sums of squares between?
how spread out condition means are
from the mean of all the scores (and therefore from each other)
What is sums of squares within?
how spread out scores are from the
condition means
What is sums of squares?
the sum of the squared deviations of some set of values from some mean
Why do we use sums of squares?
Used to quantify how spread out two or more values are in a dataset
What is sums of squares total?
how spread out scores are from the mean of all the scores
What is sums of squares between?
y how spread out condition means are from the mean of all the scores
What is sums of squares within?
how spread out scores are from the
condition means
What does SSb tell us?
- how much the groups systematically vary from
each other and shows the EXPLAINED variability of the conditions
What does SSw tell us?
- how much each person varies after accounting for
the condition they’re in - shows the variability NOT EXPLAINED by the
conditions
What is the F-test measuring?
- the ratio of explained to unexplained variability
- whether systematic variance is greater than unsystematic variance
What is correlation?
the degree to which deviations on one variable go in the same direction or the opposite direction of deviations on a second variable
How are standardised z-scores found?
how much the score deviates from the mean (in units of standard deviation)
how do we measure how much those deviations go together?
you multiply standardized deviations (Z scores) from one variable by
standardized deviations (Z scores) from a second variable,
How to find Pearson’s r value?
the average of those multiplied deviations and divide by N – 1
Why do we use vectors?
Vectors turn a nominal (categorical) variable into an interval variable, and
thereby allow us to calculate a correlation
What is a vector?
a numerical variable coded in such a way as to capture the difference
between the conditions of a categorical variable
How is correlation in a Vector the same as SSb?
tells us how
much scores on the DV go along with the conditions thus
How much of the
variability is EXPLAINED by the conditions
What does R^2 reg/Pearson’s r represent?
Pearson’s r-squared then represents the proportion of variance in the DV explained by the IV
How is the F-test similar to ANOVA in Regression?
we are trying to find out is whether the EXPLAINED variability (derived from R2 Reg) is greater than the UNEXPLAINED variability (derived from R2 Res)
= (the ratio of explained to unexplained variability)
