STAT 1200 Study Guide - Midterm Guide: Percentile Rank, Standard Score, Standard Deviation
Document Summary
Sample-- part of the population that you measure. (8. 4) standardized score = z = (observed value- mean)/standard deviation = (x - )/ . Total area under the curve = 1 or 100% Proportions-- the proportion of the population with a measurement in a certain range is equal to the area under the frequency curve over that range. Standardized score-- the # of standard deviations away from the mean an observed value is. Gives a measure of relative magnitudes--compare things relative to their own groups. Z score of the mean is always zero. Percentiles-- an observation"s percentile is the percentage of the population that is equal to or less than the observation (aka percentile rank). Percentage of observations at exactly a given value are zero. 68% fall within +/- 1 sd of mean. One variable can be perfectly predicted using the other variable. The 2 variables may be related, but perfect prediction is not possible.
