Originally posted by udontknowme:
A cognitive psychologist finds that the number of things a
group of 1-year old children can name are: [b]3, 4, 4, 5, 6, 7, 7,
10, 35.
mean and median both i can find.
but can someone help with the variance and the standard
deviation??
somehow my results and the one given in the answer key different
leh....tsk...
oh. can please show working also? so that i can see what's
wrong.....
thanks! [/b]
mean=9
The variance is computed as the average squared deviation of each
number from its mean.
(biased)variance=[summation 1 to n (xi-mean)^2]/n
=[(3-9)^2 + (4-9)^2 +...+ (35-9)^2)]/9
=796/9
=88.4
(unbiased) variance
796/8
=99.5
deviation=square root of variance.