Find the mean variance standard deviation of objects that a

Find the mean, variance, & standard deviation of objects that are 600mm, 470mm, 170mm, 430mm and 300mm tall.

600 , 470 , 170 , 430 , 300

MEan = (600 + 470 + 170 + 430 + 300) / 5 = 394

xbar = 394
Let us find the xbar - xi values :
394 - 600 = -206
394 - 470 = -76
394 - 170 = 224
394 - 430 = -36
394 - 300 = 94

(xbar - xi)^2 values now :

(-206)^2 = 42436
(-76)^2 = 5776
224^2 = 50176
(-36)^2 = 1296
94^2 = 8836

Sum all the above values :

42436 + 576 + 50176 + 1296 + 8836
108520

Divide this by n(n = number of observations = 5) :

108520

21704

So, variance = 21704

Standard deviation = sqrt(V) =sqrt(21704) = 147.32

Answers :
MEan = 394
Variance = 21704
Standard deviation = 147.32