Chapter 3 - Section 3.3 - Mean, Variance, and Standard Deviation for Grouped Data - Exercises - Page 102: 3.52

mean = 983.75 variance = 170061.1 standard deviation = 412.3846

mean = 393500/400 = 983.75 Variance =σ^2 $=(∑m^2 f-([(∑mf)]^2/N))/N-1$ $= \frac{454960000- (393500\div400)}{399}$ $=(454960000-387105625)\div400$ $=170061.1$ Standard deviation$ = \sqrt 170061.1 =412.3846$