The variance of 20 observations = 5.If each observation is multiplied by 5, then the new variance will be

Concept:

Multiplying every value by a constant:- however, will multiply the mean, median, quartiles, range, interquartile range, and standard deviation by that constant, and multiply the variance by the square of that constant.

Var X = 

Calculation:

Var X =  = 5

New observations = 5X₁, 5X₂, ...,5X₂₀

New 

=  

= 5X_old

New Var X = 

= 25 × 

= 25 × 5

= 125