Calculate the mean, variance and standard deviation for the following distribution :
   

Explanation

With the given distribution ,
`x_i = 35, 45, 55, 65, 75, 85, 95`

`f_i = 3, 7,12, 15,8,3,2`

`:. x_i f_i = 105, 315,660,975,600,255,190`

`:. sum f_i = 50`

`sum x_i f_i = 3100`

`:. Mean(barX) = (sum x_i f_i)/(sum f_i) = 3100/50 = 62`

Now, `|x_i - barx| = 27, 17,7,3,13,23, 33`

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