HDFS 129 Lecture Notes - Lecture 68: Apache Hadoop
Document Summary
Provides info regarding the strength and direction of a linear relationship b/w 2 variables. Magnitude of the correlation which indicates how strongly a change in one variable is matched by the change in the other variable. High scores on one variable is associated with high scores on second variable. High scores on one variable is associated w/ low scores on second variable. Cannot include cause & effect relationship from correlations. Example: intelligence > smart pill / placebo > Ex: smart pill (experimental group) & placebo (control group) Involves studying people of different ages at one point in time. Each bar represents a different group of people. Cohort effect characteristics of the era in which a (rather than due to age effects specifically) talk about age. We cannot talk about developmental change, can only. Differences across age groups may be due to cohort grew up.
