Is there a way to plot an "inverse or "S" trendline in excel? The resulting equation is Y = -0.136X + 16.448 which seems good > enough to me. > > Then I added a linear trendline to the chart. Also, the point with zero force looks like it's measured at a greater X than eyeball extrapolation of the last four or five points would warrant. Click on the star if you think some-1 helped you Regards Ford Register To Reply + Reply to Thread « Previous Thread | Next Thread » Thread Information Users Browsing this

Up until then, I had never seen a case. What's even more bizarre is that if I plot the data and fit a 3rd order poly trendline I get all 4 terms. Why Excel would offer to fit a trendline in that circumstance is a mystery to me, but when it does, it uses x-values of 1,2,3,... and correctly > >> calculates > >> the regression of y against those assumed x-values. > >> > >> Jerry > >> > >> "Jan M." wrote: > >> > >>

However, the equation of the trendline is off. If you reformat the trendline (change to poly or exponential, etc.) and then change it back, sometimes the equation changes. Excel displayed the > >> > following > >> > equation: Y = -0.9X + 7.5, R ^2 =1 which is way off (and it's not a > >> > rounding How to deal with players rejecting the question premise Did Sputnik 1 have attitude control?

Steve Bayliss says: Monday, August 18, 2014 at 9:28 pm Hi Jon, Firstly I would to thank you. Lewis Guest RE: Linear trendline:wrong equation Use an "XY (Scatter)" chart. Error 2: Wrong Precision The following shows the trendline for the same data in an XY chart. Many thanks in advance!

Very poetic isn't it? > > Thanks to both of you. > > Jan M. > > > > "Jon Peltier" wrote: > >> What Jerry means is don't use a Were the forces measured as the values in the first column were increasing or decreasing? When there is too much text to fit within the label, it drops enough words to fit the remainder in the box. The system returned: (22) Invalid argument The remote host or network may be down.

Jeff Perreault says: Wednesday, November 3, 2010 at 8:29 pm Jon, I'm using the LINEST function to extract the terms of a 3rd order poly using the method you've described, but Jerry "Jerry W. The time now is 03:23 AM. Error 5: Ignoring the Physics of the Problem This leads to my third point.

My data is shown below. chip says: Tuesday, February 23, 2010 at 12:37 am Thanks, Jon. Change the axis base unit setting to days, and you get the same trendline as with the scatter plot. Excel displayed the following > > equation: Y = -0.9X + 7.5, R ^2 =1 which is way off (and it's not a rounding > > problem)!!! > > > >

In Line Charts vs. Lewis Guest RE: Linear trendline:wrong equation Similarly, the bar and column charts assume that the x-axis is non-numerica categories to be treated as 1,2,3,... These are identical to the coefficients in the XY chart's trendline formula. Excel displayed the following > > equation: Y = -0.9X + 7.5, R ^2 =1 which is way off (and it's not a rounding > > problem)!!! > > > >

The resulting equation is y=0.002047x^2 - 10.371x. Lewis Use an "XY (Scatter)" chart. There's no need to mess around with the data >> range. >> >> - Jon >> ------- >> Jon Peltier, Microsoft Excel MVP >> Peltier Technical Services >> Tutorials and Custom But i got interest in trendline for two reasons- first, i saw that it fit the data very well (R^2=0.9996), so instead of calculating area using trapeziod rule, which is relatively

GSKrasle says: Friday, February 14, 2014 at 6:04 pm John, It's been a long time since I've looked at this post; interesting that it's still popping! A 4th order polynomial fit has no physical significance in any model I've ever heard of. It makes a "nice" curve, but is valid for interpolation only, for purposes of looking Lewis" wrote: > Use an "XY (Scatter)" chart. > > When you selected a "Line" chart, you (by definition) told Excel that your > x-axis was categorical instead of numeric, and A poly fit is probably fine.

To start viewing messages, select the forum that you want to visit from the selection below. When you selected a "Line" chart, you (by definition) told Excel that your x-axis was categorical instead of numeric, and that what you provided for the x-axis was a set of ERROR The requested URL could not be retrieved The following error was encountered while trying to retrieve the URL: http://0.0.0.10/ Connection to 0.0.0.10 failed. Very poetic isn't it? >> > >> > Thanks to both of you. >> > >> > Jan M. >> > >> > >> > >> > "Jon Peltier" wrote: >>

The resulting equation is Y = -0.136X + 16.448 which > >> > seems good > >> > enough to me. > >> > > >> > Then I added a It may seems trivial to you, but I assure you that it is > not > to me (maybe because I'm using a french version). > > Thanks. > > Jan Applying a Trendline Adding a trendline is straightforward. And how do I fix this?

Jon Peltier says: Tuesday, February 23, 2010 at 12:14 am Chip - I've heard lots of complaints about accuracy of Excel's statistical computations, enough that I can't keep track of what's When I plug the X values back to the equation, The new Y's don't fall on the curve. Lewis" wrote: >> > >> >> Use an "XY (Scatter)" chart. >> >> >> >> When you selected a "Line" chart, you (by definition) told Excel that >> >> your >> and correctly calculates the regression of y against those assumed x-values.

Results 1 to 5 of 5 LinkBack LinkBack URL About LinkBacks Bookmark & Share Add Thread to del.icio.usTweet this thread Thread Tools Show Printable Version Email this Page… Subscribe to this It is the wrong kind of >> chart >> to use to show relationships between two variables, even if you are not >> trying to generate statistics on it. Excel displayed the following > > equation: Y = -0.9X + 7.5, R ^2 =1 which is way off (and it's not a rounding > > problem)!!! > > > > This is Yet Another Reason not to use 3D charts, when will you ever learn?

That the data is constant over time. When we plug the RPM data and the fitting coefficients into the trendline equation, we get the following horrendous match.