EPPS 2302 Lecture Notes - Lecture 12: Weighted Arithmetic Mean, Sample Size Determination, Standard Deviation
23 Feb 2016
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Document Summary
Key features of quantitative: measure of central tendency - typical observation (center of the data): mean, median, mode. Variability of the data: spread around the center to know everything about the story, not just the average. Arithmetic mean ( ) [mew] is computed using all individuals in a population. Scores and x"s: 23, 36, 23, 18, 5, 26, 43. Group is close to population mean but not always the same every time. Sample arithmetic means x-bar is using sample data. Scores (and x"s): 80, 85, 90, 95, 100 n is 5. = 450 = 80 + 85 + 90 + 95 + 100. Average is a single score that represents, not the typical score. ut. Weighted mean - special case of mean calculation when there"s more than one of each score. Median - midpoint, 50% fall below and 50% fall above. Median: use when there are extreme scores or outliers to avoid having those being weighted.
