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Thread Subject:
confidence intervals of large matrix

Subject: confidence intervals of large matrix

From: Kirk

Date: 9 Feb, 2009 22:50:18

Message: 1 of 3

I am looking for suggestions as to how to approach the problem of plotting continuous confidence intervals of some data in a rather large matrix. The matrix dimensions are 13200 x 100. Each column represent an iteration of simulated data. Therefor we have 13200 observations (as rows).

I would like to graphically represent all 100 columns by plotting the mean, and then, some kind of continuous confidence interval (say 95%) about the mean line. I am looking at the file 'CONFPLOT' from the file exchange, but I'm not sure if this is the right approach? Or if it is, how to get it to handle all my data columns? Is this a two part step of calculating a mean and std across columns, and then calling CONFPLOT, or should I look elsewhere?

Subject: confidence intervals of large matrix

From: jrenfree

Date: 10 Feb, 2009 00:49:11

Message: 2 of 3

Usually for confidence intervals I just use +- 2 std.

So if you have 13,200 observation using 100 iterations, you first find
the std:

stdev =3D std(data, 0, 2)

Then you're left with a standard deviation for each observation using
the 100 iterations.

Then take the mean, plot that, and plot the mean +- 2 std.

You can also use the function errorbar after you calculat the standard
deviations.

On Feb 9, 2:50=A0pm, "Kirk" <kwythers.nos...@umn.edu> wrote:
> I am looking for suggestions as to how to approach the problem of plottin=
g =A0continuous confidence intervals of some data in a rather large matrix.=
 The matrix dimensions are 13200 x 100. Each column represent an iteration =
of simulated data. Therefor we have 13200 observations (as rows).
>
> I would like to graphically represent all 100 columns by plotting the mea=
n, and then, some kind of continuous confidence interval (say 95%) about th=
e mean line. I am looking at the file 'CONFPLOT' from the file exchange, bu=
t I'm not sure if this is the right approach? Or if it is, how to get it to=
 handle all my data columns? Is this a two part step of calculating a mean =
and std across columns, and then calling CONFPLOT, or should I look elsewhe=
re?

Subject: confidence intervals of large matrix

From: Lixiang Xiong

Date: 25 Jun, 2009 10:53:01

Message: 3 of 3

As I understand, you do 100 sets of trials on simulation.
For each set, you obtain a mean vaule.
So, now you actually have 100 mean values.

You want to calculate the 95% confidence interval for the mean value based on such 100 mean values.

Am I right?

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