STAT 2507 Lecture Notes - Lecture 2: Squared Deviations From The Mean, Standard Deviation, Quartile
11 Sep 2018
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Common measures of centre; mean, median, and mode. Arithmetic mean or average: refer to chapter 2 page 4 for formula, you can think of the mean as the balancing point or fulcrum of set of measurements. Median: middle position: 0. 5(n+1, arranged from smallest to largest. Exercise 1: mode= 50, mean= 52, median =50, median, and mode stays the same, mean= 252, 1065 is the outlier. Range r is the simplest measure of variability. The range, r, of a set of measurements, n, is defined as the difference between the largest and smallest measurements. Variance of a population of n measurements is the average of squared deviations of the measurements about their mean u. (sigma squared: refer to chapter 2 page 12, only use for whole population. Sample variance is the sum of squared deviations of the measurements about their mean: refer to chapter 2 page 13. The empirical rule: given a distribution of measurements that is approximately mound-shape:
