R-squared can't handle changes?

AstroZack shared this question 1 month ago
Needs Answer

Hey everyone, I am trying use an r-squared as part of something for my students. It appears to work well to begin with, but if I go back and change the value(s) for even one of the points in the spreadsheet then RSquare goes to "undefined". What's wrong?


Is there a way to set Rsquare up so that it changes along with any point values that are updated in the spreadsheet? I really need this feature to be "flexible" in this way.

Comments (2)

photo
1

Please post your .ggb file and say what you did exactly to get the problem

photo
1

I need to have everything set up so that students simply enter their data and use the sliders to match the line to their data (eyeballing a line of best fit). Geogebra graphs the data and performs an r-squared test to gauge the line of best fit. The challenge is that students will not always be entering the same number of data points each time.


Focusing on just the first set of data: students enter their data in Columns A and B. It is turned into points to be graphed in Column G. I've also created a list for the data points in Column G titled "ListIo". This allowed me to do an RSquare (simple titled "a" for the time being). However, when I go to delete some of the sample data I have in Columns A and B, RSquare becomes undefined.


How can I set this up so that RSquare is defined and works no matter how many data points the students enter?

© 2020 International GeoGebra Institute