Calculating Weighted Returns Variance, Standard Deviation everyone, calculator, standard, question, example

richer

Hey everyone.

I just have a quick question. Can someone please tell me how I could calculate the variance and standard deviation of weighted returns?

For example:
Probability Return
Recession .3 .10
Normal .6 .15
Expand .1 .25

And the question says to calculate the standard deviation + variance, any idea how I could do that in the TI calculator?

Normally if the returns were not weighted, I would put into the Data list, then go to 1-V of the Stat section.

But how could i input the weights?

I tried putting the weights in the frequency (the Y), then go to Stat looking for 2-Var but nothing is there.

Can someone please clarify, as for sure this question is very likely to appear and it would take long to do it manually (if you could even remember).

Thanks a lot for your help in advance, and best of luck to everyone.

Mechanic

I don't think you can do probability weighted calculations on TI

JGovender

Type weights as Y's, but in percentages instead of decimals (they should sum up to 100) and you should see the weighted mean and SD in 1-V.

Bulla564

I think you should learn the very easy formula and not rely on your calculator. That formula is central to lots of quant calculations in life and perhaps later on other CFA exams. In other words, dont be such a wuss.

Siddimaula

Found out how to do it, put the weights in Y (don't put decimals for the percentages), put the returns (decimal form) into X and then just go to 1-VAR in Stat and that will save you a lot of time on the exam.



Edited 1 time(s). Last edit at Monday, May 16, 2011 at 03:17PM by ext.

koba

What are you going to do if you have to calculate this for a portfolio having at least two stocks?

JRossSter

what is the 1-Var or 2-Var in the TI ? how do u get there ?
could you please post the result of this simple example u gave above ? thanks