STATS 2B03 Lecture 3: Lecture 3 - Jan 12
24 Jan 2016
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Document Summary
The average of a sample (x1, x2, ,xn) is called the sample mean or mean and is denoted by xx, The average of the population x1, x2, xn is called population mean and is denoted by . Note: n is the population size; n is the sample size. The mode of a data set is the value that occurs most often. In a grouped data set, the modal class is the group with the largest frequency. The range r of a data set is the largest value (xl) minus the smallest value (xs) The sample variance (or variance) of a data set x1, x2, . ,xn is defined by. The population variance of a population of values x1,x2,,xn is defined by: Example: 55, 63, 72, 41, 87, 75, 64, 60. R= 87-41=46x= 64. 625 (never round if needed for another calculation!) *** do not use a rounded x (bar) or average for the s squared.
