# Thread: Statistics : to calculate mean and variance

1. ## Statistics : to calculate mean and variance

suppose we have a problem like this

Properties

A B C D E F G
1 AA1 1.8 2.5 3.8 1.9 -3.5 -3.5 -3.2
2 AA2 2.95 1.69 -0.83 -2.52 -0.33 1.61 2.19
3 AA3 4.12 5.2 -1.65 -0.48 1.39 -1.24 3.25
4 AA4 0.6 -1.19 -1.2 -0.25 -0.62 1.21 2.06
5 AA5 1.73 1.14 1.19 1.56 1.16 1.41 1.58
6 AA6 1.9 1.8 1.95 2 1.55 1.75 2.1
7 AA7 1.75 -1.27 -1.66 0.03 -1.5 0.51 1.55

Then the value of each property Pkm (k=1...7,m=1....7)
where k ---> AA1.......AA7
m----> A....G

so
P1 =( Pkm - Uk/Sk )

Where Uk defined as mean of property k and is equal to 1\7 * Pkm
and Sk is defined as variance of property k and is eaual to 1/6(Pkm-Uk)2

So we want to calculate P1 so how to proceed with this problem??

2. Honestly, the notation of the problem is unclear to me. Your definitions of mean and variance look like they should include a sum -- is that what Pkm is?

3. Here defintion of Pkm is just like normal X value when used in calculating mean

Uk = 1/N X
where Uk is mean and X is just same as Pkm.
Here we are referring to the above mentioned question where X or Pkm can be defined ..
K=1...7 or AA1....AA7
m=1...7 or A.....G

So it is needed to calculate mean and variance ....