2. Mean (Average) is defined as numerical average Sample Mean is given by Population Mean is denoted by EX: Sample Mean of 1, 4, 2, 1 is_ 1.4 Measures of Variability R =X Range is defined as max - X min Population Variance is denoted by E (X, - 8) Sample Variance is given by $2 n-1 Population Standard Deviation is given by Sample Standard Deviation is given by