Chapter 3 - Section 3.3 - Mean, Variance, and Standard Deviation for Grouped Data - Exercises - Page 103: 3.53

$Mean = 13.0288$ $Variance = 78.2648$ $ Standard Deviation = 8.8467$

Mean $= 5211.5\div400 = 13.0288$ Variance $=σ^2 =(∑m^2 f-([(∑mf)]^2/N))/N = \frac{99127- (27159732\div400)}{399} =(99127-67899.33)\div399 =78.2648$ Standard Deviation $= \sqrt 78.2648 = 8.8467$