Calibration code

4 views (last 30 days)
Frandy
Frandy on 9 Jan 2012
Can anyone help, I am trying to create a code that will allow me to calibrate 2000 data points that correspond to a time of 0 to 4 secs. I want to create a linear regression using only .5 to .7 secs of the data. I tried using polyfit but it just isnt working, so any ideas?
  3 Comments
Walter Roberson
Walter Roberson on 9 Jan 2012
Do you have evidence that the response curve is polynomial ?
0.5 seconds of (2000 points / 4 seconds) works out to be 250 points. What polynomial order are you using to fit those 250 points?
Sean de Wolski
Sean de Wolski on 9 Jan 2012
And even if those 250 points are linear, remember the dangers of extrapolating the others:
Mark Twain says in Life on the Mississippi (1884):
“In the space of one hundred and seventy six years the Lower Mississippi has shortened itself two hundred and forty-two miles. That is an average of a trifle over a mile and a third per year. Therefore, any calm person, who is not blind or idiotic, can see that in the Old Oölitic Silurian Period, just a million years ago next November, the Lower Mississippi was upwards of one million three hundred thousand miles long, and stuck out over the Gulf of Mexico like a fishing-pole. And by the same token any person can see that seven hundred and forty-two years from now the Lower Mississippi will be only a mile and three-quarters long, and Cairo [Illinois] and New Orleans will have joined their streets together and be plodding comfortably along under a single mayor and a mutual board of aldermen. There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact.”

Sign in to comment.

Answers (0)

Categories

Find more on Historical Contests in Help Center and File Exchange

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!