Best Fit to Data

[alextbates]

I am a teacher at an International School in Switzerland and am about to start some IB coursework on Tide Modelling with my IB2 group.

I had a look at the Autograph video tutorial on how to do this and can perform all steps until it comes to the Best Fit to Data option.  When I right click I get a different menu with more complicated looking functions such as evolute, symptote etc.  

All I want to be able to do is to fit a curve to my tide modelling data set.  I need to explain this to the students by Friday so urgent help is needed.

Thanks, Alex

[Simon]

Hi alextbates,

Basically to fit a function with constants to a set of points you need two things:

1. The set of points (e.g. measurements) that you want to fit
2. An equation with constants in it (e.g. y = asin(bx + c) + d) plotted.

Then select the points and the function and right-click, the Best Fit to Data option should be at the bottom.

The Evolute and Asymptote options will appear if only the plot of the equation is selected and not the points.  Because the right-click menu is context-sensitive it only shows you the options which are appropriate for the currently selected objects.

Hope this helps,

Simon

[alextbates]

It still doesn\'t have the same options.  I get a much bigger list of options than on the help file.  I have tried selecting the y=asin(bx+c)+d as well as the original data points from the tide modelling curve that I have and the closest that I can get to a best fit is a polynomial of order 6.  However, the help file states that I should be able to modify the a, b, c and d values using autograph but this option is not available on my menu.

The menu that I get up either shows

1)  Enter Equation at the top and Maclaurin Series at the bottom

or if I select the data points

2) Enter Equation at the top with an option to have best fit which is for a polynomial up to order 6 in the middle of the menu and then Matrix Transformation at the bottom of the menu


Please could you shed some more light on this?

Thanks, Alex

[Simon]

Could you please send me some screenshots and save an agg file and send that as well.  Please email to support AT autograph HYPHEN maths DOT com.  (Remove spaces and replace words in capitals with appropriate symbols.)

Thanks,

Simon