PSY 250 Lecture Notes - Lecture 9: Percentile Rank, Standard Score, Central Tendency
Document Summary
Is: procedures that use ds from sample to test hypotheses about pop. Set of data or scores (summarized w/ ds) Location of indie scores: percentile ranks, z scores. Central tendency: how participants scored overall, a typical score in a dist"n. Variability: how widely is dist"n of scores spread. Mean is used w/ interval or ratio scales. Median is score that divides the group in half and is used w/ ordinal, interval, ratio scales. Outliers are extremely high or low scores in dist"n. They pull mean towards top or bottom of range. If present, usually want to use median instead. Crude measure b/c ignores all scores b/t lowest and highest score. Becomes larger as more ppl have scores that lie farther from the mean value. Expressed in variable"s original unit of measurement (standardized) Variance represents the total amount of similarity or dissimilarity of scores w/in a sample.
