QMS 102 Lecture Notes - Lecture 4: Standard Deviation, Box Plot, Weighted Arithmetic Mean

• School: Ryerson University
• Department: Quantitative Methods
• Course: QMS 102
• Professor: Gunawardena Egodawatte

Document Summary

In this lesson, you will learn the measures of central tendency (mean, median, mode) and variability (range, inter quartile range, variance, standard deviation) and to graph a box-whisker plot. We can characterize any data set by measuring its central tendency, variation, and shape. Central tendency values give us a middle or average point of the data. Variability measures the spread or dispersion of the data. We denote sample mean by x , population mean by , sample size by n , and population size by n . Mean is the average value of the data. Sample mean is calculated by the formula x n x. Extreme values in the data distribution do affect the mean. Here, we have to use the weighted average because different stores sold different number of printers. Average price per printer = (cid:2872)(cid:2868) (cid:2874)(cid:2868)(cid:2868)+(cid:2874)(cid:2868) (cid:2873)(cid:2873)(cid:2868)+(cid:2869)(cid:2874)(cid:2868) (cid:2872)(cid:2870)(cid:2873)+(cid:2877)(cid:2868) (cid:2873)(cid:2868)(cid:2868)+(cid:2873)(cid:2868) (cid:2874)(cid:2868)(cid:2868) (cid:2872)(cid:2868)(cid:2868) x.