# Mathematica: find mean value of an increasing list

1. Oct 9, 2009

### skitapa

I have a list L={a_{1}, ..., a_{n}}. I would like to find the mean of
L_{i} := {a_{1}, ... , a_{i}} for each 1<i<n, and then plot the means.
How do to do that in a smart way?

Last edited: Oct 9, 2009
2. Oct 9, 2009

### Hepth

I'm not suite sure what you're asking but there are build in mean funcitons.

So couldn't you do something like :

MeanList= List[Mean[L],{i,0,n}]
ListPlot[MeanList]

3. Oct 9, 2009

### skitapa

The L_{i} can be constucted by the Take function. But it seems hard to plot the means afterwards. Thats the real problem, how to get something that can be plotted

4. Oct 9, 2009

### Hepth

Well, your means will be scalars, one for each list, yes? well, make a list out of them and listplot.

5. Oct 9, 2009

### Hepth

L = {11, 12, 13, 14, 15, 16}
MeanList = Table[Mean[Take[L, i]], {i, 1, 6}]
ListPlot[MeanList]

6. Oct 9, 2009

### skitapa

Thank you very much.
I did generate the means by:
Code (Text):
For[i = 1, i < 1000, i++, Print[Mean[Take[R, i]]]]
and from there I was not able to make a list will all the means. Anyhow, your way was way better.