Find the mean variance and standard deviation using short-cut method

Explanation

Let assumed mean `A=92.5` and `h=5`
Mean `barx=A+(sumf_(i)d_(i))/(sumf_(i))xxh=62.5+(6xx5)/60=93`
Variance `sigma^(2)=h^(2)[((sumf_(i)d_(i)^(2)))/N-((sumf_(i)d_(i))/N)^(2)]`
`=5^(2)[254/60-(6/60)^(2)]`
`=25/(60^(2))[15240-36]`
`=1/144xx15204=105.58`
Standard deviation `=sqrt(105.58)`
`=10.28`