Chart2/TrendLines

Add polynomial regression type

• Different types of regression lines are already offered: linear regression, exponential regression. But a polynomial regression curve is still missing. A macro on this site offers a workaround (french only):
• http://oooconv.free.fr/fitoo/fitoo_fr.html
• covered in http://www.openoffice.org/issues/show_bug.cgi?id=20819

Allow more than one regression line for one series

• covered in http://www.openoffice.org/issues/show_bug.cgi?id=64813

Extrapolating of trend lines

• Trend lines should also allow extrapolating. If data ranges from 1 to 5 but that x axes range from -2 to 10, then the trend line should display from -2 to +10.
• In Excel, the setting is called forward forecast and backward forecast.
• covered in http://www.openoffice.org/issues/show_bug.cgi?id=5085

Mean value for X and center of gravity

• Get the mean value not only for Y but also for X. A special symbol could mark the intersection point (the center of gravity).
• covered in http://www.openoffice.org/issues/show_bug.cgi?id=64816

Error bar for X

• Error bar for X added to the existent Y one
• covered in http://www.openoffice.org/issues/show_bug.cgi?id=42946