QMS 102 Lecture Notes - Lecture 5: Interquartile Range, Variance, Statistical Inference

• School: Ryerson University
• Department: Quantitative Methods
• Course: QMS 102
• Professor: Nursel Ruzgar

Document Summary

Measures of variation: range, variance, standard deviation, coefficient of variation. Measures of variability give information on the spread or variability or dispersion of data. Whereas measures of central tendency give a single value to represent the data set. Measures of variation: summary characteristics: the more spread out or dispersed the data are, the larger the range, Stock a and stock b have the same deviation, but stock b is less variable relative to its (average) price. Shape of a distribution: describes how data are distributed, skewness, measures the amount of asymmetry in a distribution, left-skewed, mean < median (skewness statistic <0, symmetric, mean = median (statistic =0, right-skewed, mean > median (statistic >0) 3: kurtosis, measures the relative concentration of values in the center of a distribution as compared with the tails, flatter than bell shaped (rectangle) (<0, bell shaped (regular looking peak) (=0, sharper peak than bell shaped (triangle) (>0)