start by finding the mean
do you mean `2.5` ?
mean = 1*.4+2*.1+3*.1+4*.4 = 2.5
yes 2.5 sorry.
good, find the deviation from mean for each of the data values
subtract mean from each data value
sub. 2.5 to each point?
Yes, work \(\large x_i - 2.5\) for each data value
-1.5, -.5, .5, 1.5
square each of them
-2.25, -.25, .25, 2.25?
when you square, the negative sign disappears thats precicely the reason we square here ok
(-1.5)^2 = +2.25 it is not -2.25
ops, crap. I put it in my calculator wrong then. :/
@rational so what do I do now?
hey still here ?
sry was on mobile
okay where are we
Its okay :) 2.25 fix from negative to positive :)
multiply each of those by the corresponding probabilities, then add them up
Perfect! 1.85 is the variance
we basically used below formula |dw:1432819854547:dw|