Description: After making a graph with spreadsheet data, when you insert a TREND LINE and have CALC calculate the linear equation for the data, the Y-INTERCEPT is incorrect. It appears to reflect the y-intercept of the visualized graph and not of the data. Eg if your graph has an x-axis starting at other than zero it will give the y-intercept as if the first datapoint were x=0. Steps to Reproduce: 1. Have graph data, eg one column of 11..20 (x) and another of 11..20 (y) 2. Insert a graph of that data 3. Insert a trend line and show the equation. It is f(x)=x+10 WRONG instead of f(x)=x (CORRECT) 4. Actually, less-simple data gives a wrong slope (m) for the equation as well, so the entire algorithm might be wonky. Email for detailed examples and graphs. Actual Results: see above Expected Results: see above Reproducible: Always User Profile Reset: No Additional Info:
Created attachment 156582 [details] Example of Error
Choose the chart type XY (Scatter). Then you can get correct equations of trend lines. *** This bug has been marked as a duplicate of bug 42380 ***
Great but maybe at least disable the broken feature? Many are math-illiterats and wouldn't notice the numbers are wrong.
I think this feature is misleading, but it works even if X data are non-numeric.