PO218 Lecture Notes - Lecture 3: Interquartile Range, Interval Ratio, Quartile
Document Summary
2011] than that of canadians [,000 in 2011] January 19, 2016: presented in a frequency distribution = highest peak. Nominal level variables measure of dispersion variation ratio: variation ratio (v): is one of only a few measures of dispersion for nominal level variables. If n is odd: the median is the score of the middle case. If n is even: the median is the average of the scores of the two middle cases. January 19, 2016: percentile is the point below which a specific percentage of cases fall. Characteristics of the mean: all scores cancel out around the mean, the mean is the point of minimized variation. Least squares principle : the mean uses all the scores, the mean is the point of minimized variation. The sum will always be greater than 388: for example, the sum of the squared differences around 77 is 393. If there are some very high or low scores, the mean may be misleading.
