They seem to integrate extremely well into Excel. [They do have a quick flash screen explaining that the author is looking for a job].

Use the ‘standard error of regression’ from the ARMA output worksheet for the standard deviation of the random number series, in a reconstruction.

Incidently to create a volatile normally-distributed random number series using Excel’s inbuilt functions: Drag down RAND (which is volatile) and then drag down NORMINV setting its ‘probability’ value to the value given by the RAND function in the same row.

-As clear as mud, I suspect!

]]>I sort of agree with TCO, it would be nice to have a single location where simple autocorrelation tutorial could live.

To make matters a bit worse than they are, presently (‘gambling runs’ is falling off the bottom of the page):

To make an AR1 series (value 0.9, say)in Excel

Create a column of normally distributed random numbers (tools=> data analysis) with mean zero and SD 1

Place a value of zero at the top of the column adjacent to it.

Below this zero make the cell’s value equal to 0.9 times the value above it (in this case zero) and add the adajcent random number.

Drag this formula down.

This is a bit dull; to liven things up a bit download the 30 day free demo of Resampling Stats for Excel add-in http://www.resample.com

The program has a volatile random number generator (RXL normal)function so when one changes any cell on the page the random series is regenerated afresh (one can also stick a trend lines through the series and use its ‘resample and score’ to do a few thousand runs and plot these out with it’s autobin histogram )

Im not too clear on the MA1 part but I beleive it refers to random series itself: A series with an MA1 of 0.3 adds the error of the adjacent random cell plus 0.3 times the value of the random no. above it

-Please correct me if I have this wrong.

1. What is white noise. What is red noise? A reasonably clear explanation can be found at this link. It refers to music but can apply to anything with a “frequency”.

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TCO, apologies if I’m being thick, but what is DOE ?

]]>On content:

1. What is white noise. What is red noise?

2. I’m still thinking about run order which is a variable in DOE. This would seem to equate to time in these climate studies. Do you think that we handle run order appropriately in manufacturing based studies? I wonder if there is some way to help equate what is done with run order in DOE with the concerns about trend estimation.