Chapter 3 - Section 3.3 - Mean, Variance, and Standard Deviation for Grouped Data - Exercises - Page 102: 3.48

Mean = $752\div80 = 9.4$ Variance $=σ^2$ $=(∑m^2 f-([(∑mf)]^2/N))/N$ $= \frac{10048- (565504\div80)}{79}$ $= 37.7114$ Standard Deviation =$ \sqrt 37.7114$ =6.141

Mean = $752\div80 = 9.4$ Variance $=σ^2$ $=(∑m^2 f-([(∑mf)]^2/N))/N$ $= \frac{10048- (565504\div80)}{79}$ $= 37.7114$ Standard Deviation =$ \sqrt 37.7114$ =6.141