PSYC 2030 Chapter 4: PSYC 2030 Chapter 4 Notes
5 Jun 2018
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PSYC 2030 Chapter 4 Notes
Introduction
Absolute Value
• The absolute value of r (disregarding its sign) tells us the strength of the relationship.
• Thus, correlation coefficients of –.70 and +.70 are of equal strength, and both are
stronger than a moderate correlation of .30.
• An r of .00 indicates that the two variables are not systematically related.
• The sign of the correlation coefficient indicates the direction of the relationship.
• If the sign is positive, this means that as one variable increases, the other variable also
increases.
• For example, height and weight are positively correlated
• As children grow taller, they tend to get heavier (Tanner, 1990). Negative correlations
indicate inverse relationships
• As one variable increases, the other decreases.
• For example, Brett Friedman and her colleagues (Friedman et al., 2007) examined
attention problems in children and found that the more attention problems children
had when they were young, the poorer their thinking skills were when they were in late
adolescence
• Among elementary school students, for example, aggression and popularity are
negatively correlated
• Children who behave more aggressively tend to be less popular with their peers (Crick,
1996).
• No let’s return to our hypothesized positie relationship eteen teleised iolene
and hildren’s aggressie ehaiour.
• A number of investigators have conducted correlational studies similar to the one we
have designed, and the results (reviewed in Liebert & Sprafkin, 1988) suggest a
moderate positive correlation (between +.30 and +.50) between the two variables of
interest
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