Hi David,

First of - your material is really oustanding. From my perspective as a trainer it’s is really making sure that all senses are used during the learning process.

I am reviewing Quant Study Notes again and got stuck at a very basic case. While I know that basically you can add the variance of two independent random variables together, the result I get when calculating it with a spreadsheet similarly to the one you used for the variance of one die is different.

WA X X P WA X^2
0.055555556 2 1 0.111111111
0.166666667 3 2 0.5
0.444444444 4 4 1.777777778
0.555555556 5 4 2.777777778
0.666666667 6 4 4
1.166666667 7 6 8.166666667
0.888888889 8 4 7.111111111
1 9 4 9
1.111111111 10 4 11.11111111
0.611111111 11 2 6.722222222
0.333333333 12 1 4
7 36 55.27777778 49 6.277777778

This should result in 5.83 not 6.28, right? What I am doing wrong?

Many thanks

Mike

Hi Mike,

What might be sad is that i can read your code I think you are mostly right, just maybe something wrong in the middle. Here is my try in EditGrid.

I like your experiment, I think it will make a nice addition to the member library!. You are totally right to check it with, VAR(Die+Die) = VAR(Die) + VAR(Die) + 2COV(Die,Die) where the last = 0 if independent, so it should be 5.83. (Thanks for your compliment, really appreciate that...)

David

Hi David, many thanks for that. Great, thanks to your editgrid I now understand that I got the # of ways wrong, while the rest was correct.
I really think you master the use of media perfectly for distance learning, I saw in your blog you have an general interest in this area, too. I hope to see that some years down the line your business will expand way beyond the FRM, you have the platform and the processes in place! All the best for that! Mike