PSY201H1 Lecture Notes - Lecture 4: Quartile, Standard Deviation, Statistical Inference
Document Summary
How much clustered together or scattered apart the scores are in a distribution: range (difference between higher and lowest, interquartile range, variants, standard deviation more precise means of spreadness or clusterdness. Understand the general purpose for measuring variability and should be able to recognize the difference between scores with high variability vs. score with low variability. Define and calculate the range, and realize this is a relatively crude measure of variability. Understand the concept of standard deviation as a measure of the standard distance from the mean. Be able to calculate ss (sum of squared deviations) variance, and standard deviation for a sample and for a population. The goal for variability is to obtain a measure of how spread out the scores are in a distribution. A measure of variability usually accompanies a measure of central tendency as basic descriptive statistics for a set of scores. Not all scores are the same chunks (0 variability) measures how big differences are.
