Trendlines in Numbers 09

I am trying to make a trendline in Numbers 09 but I can't set the trendline to go through the origin (0,0). Is there a way to do this?

Linear trendline makes this easy. You can create a datapoint that is directly on the line and that will get the line to go through zero. Put a negative number in your X column then use the FORECAST function to calculate the Y. Select this row along with the rest of your data for your chart. Set the min for the X axis to zero so this fake "datapoint" doesn't actually show on the chart. Similarly, if you want the trendline to continue out to the right past the end of your X data, put in a larger X, use FORECAST to determine the corresponding Y, and set the max for the X axis to be less than that X. Neither of these points will affect the trendline (other than extending it).

Similar Messages

  • What statistical methodology is used to create a trendline in numbers

    I am doing a paper and have a trendline generated by Numbers on a scatter plot, and would like to avoid confirming my 'm' and 'b' values with a least squares calculation.  Does anybody know what methodology is used in the algorithm that calculates trendlines in numbers so I can report that rather than doing the calculation myself?

    Hi Michael,
    It's really surprising what one can learn by reading the documentation supplied by Apple.
    A search of the iWork Formulas and Functions User Guide using 'least squares' as the search term brings up two hits, both describing the LINEST function.
    The same search in the Numbers '09 User Guide returns no results, but a search on 'trendline' returns many, with most occuring on two consecutive pages. Clicking one of these brings up the article Showing Trendlines in Charts, which doesn't directly mention "least squares", but does imply that method in the following note (emphasis added):
    To see the R-squared value that was used to calculate a trendline, select the line, and then select Show R^2 Value. You can drag this number to wherever you want it to appear on the sheet.
    Both these invaluable user guides are available for download via the Help menu in Numbers '09.
    Regards,
    Barry

  • Is there any way of extending a polynomial trendline in Numbers '09?

    Hi,
    The question title says it all really.  Is there any way of extending a polynomial trendline in Numbers '09, beyond the data that I currently have?  I can do this in Excel, but would like to be able to do this in Numbers too.
    Thanks,
    Nick

    Unfortunately there is no "forecast" feature for trendlines in Numbers. Wayne showed how to use the trendline equation from the chart to create additional data points for the chart.  This is by far the simplest way to do it in Numbers but it has two drawbacks:
    If your data changes, you'll need to manually readjust the coefficients for your forecasted point(s).
    The precision of the coefficients is only three decimal places. The forecasted Y values using these coefficients might not be as accurate as you would like. For example, compare the forecasted Y value in Wayne's table at X=20 to the one in the table below.
    You can avoid both problems by calculating the trendline coefficients in your table using the LINEST function. it is a little more work in the setup but it might save you time in the long run if your data changes a lot. Here is an example of for 2nd order polynomial:
    The last "real" data point is in row 10.
    Formula for column D =A
    Formula for column E =A*A
    F2 = the coefficient for X^2 =INDEX(LINEST(B2:B10,D2:E10),1)
    G2 = the coefficient for X =INDEX(LINEST(B2:B10,D2:E10),2)
    H2 = the constant =INDEX(LINEST(B2:B10,D2:E10),3)
    Note: If you later need to add an additional data point at the end of your data, go to the last row of your data (in this example it is row 10) and "add row below".  This way the formulas for the coefficients will adjust automatically to include the new row.

  • How do I add a trendline in numbers for iPad?

    I want to add a trendline to a 2D scatter chart in numbers on my iPad Air. Can anyone help me with this?

    if you want to add a linear best fit line you can get the parameters for that line from your existing data and make a NEW series:
    Using my previous charts you can add a new table (in this case below the chart) used to calculate the slope (m) and the y-intercept (b) for each of the original series.  Then you can use those two values with the original X values to construct a best fit line.  The bottom table is named "Best Fit Constants" and is constructed:
    B1=INDEX(LINEST(Data :: C,Data :: B,TRUE), 2)
    B2=INDEX(LINEST(Data :: C,Data :: B,TRUE), 1)
    D1=INDEX(LINEST(Data :: E,Data :: D,TRUE), 2)
    D2=INDEX(LINEST(Data :: E,Data :: D,TRUE), 1)
    The original table (which I named "Data") is constructed as follows:
    F2=B2
    G2=Best Fit Constants :: $B$1+Best Fit Constants :: $B$2*F2
    H2=D2
    I2=Best Fit Constants :: $D$1+Best Fit Constants :: $D$2*H2
    select F2 thru I2 and fill down as needed.  Expand the graph range by selecting the chart,
    then dragging the data range controls (in the table) to include the best fit data

  • Adding trendline in Numbers for iPad

    Can I add trendlines for my charts in Numbers for iPad?

    Don't type the two letters "nu" but the three "ios" ones.
    You will get two entries :
    iMovie for iOS
    and
    iWork for iOS (which is ridiculous because this product doesn't exist).
    Clicking on this late entry you will enter a community grouping questions upon the three apps.
    Click the button "Refine this list" to restrict to Numbers.
    I already asked the forum staff to change this odd behavior so that
    typing nu offer Numbers 4 iOS
    as well as Numbers 4 mac OS
    And of course, same request for Keynote and Pages.
    Wait and see.
    Yvan KOENIG (VALLAURIS, France) samedi 25 juin 2011 12:08:36
    iMac 21”5, i7, 2.8 GHz, 4 Gbytes, 1 Tbytes, mac OS X 10.6.7
    Please : Search for questions similar to your own before submitting them to the community
    To be the AW6 successor, iWork MUST integrate a TRUE DB, not a list organizer !

  • Can a trendline in Numbers be extended to see predictions without adding data that does not exist?

    The spread sheet that I'm working with adds daily data over a 6 month timeframe. The trendline stops at the newest data point. I would like to know what to expect in 6 months so I can make adjustments to adjust progress. I would like to do this without adding false data that I don't have yet.
    Thanks

    If you notice in my first response... the top screenshot shows a plot with a trend line that shows the equation.  I used the slope and offset in the formula that extend the "prediction"
    you could use the forecast() or linest() function to create this prediction with out the trend line.
    Here is another example:
    I entered actual (but made up) data in columns A and B
    then I calculate the slope and intercept of that data in column F
    F3=INDEX(LINEST(B2:B6,A2:A6,TRUE,TRUE), 1)
    F4=INDEX(LINEST(B2:B6,A2:A6,TRUE,TRUE), 2)
    now in columns C and D I enter X values and calculate predicted Y values using the slope and intercepts:
    D2=$F$3×C2+$F$4
    select D2 and fill down as needed

  • Adding a trendline in Numbers

    Can I add trend line for my charts in Numbers for iPad?

    If you notice in my first response... the top screenshot shows a plot with a trend line that shows the equation.  I used the slope and offset in the formula that extend the "prediction"
    you could use the forecast() or linest() function to create this prediction with out the trend line.
    Here is another example:
    I entered actual (but made up) data in columns A and B
    then I calculate the slope and intercept of that data in column F
    F3=INDEX(LINEST(B2:B6,A2:A6,TRUE,TRUE), 1)
    F4=INDEX(LINEST(B2:B6,A2:A6,TRUE,TRUE), 2)
    now in columns C and D I enter X values and calculate predicted Y values using the slope and intercepts:
    D2=$F$3×C2+$F$4
    select D2 and fill down as needed

  • Logarithmic Trendline

    I am testing out iWork '09, hoping to get away from Office. So, naturally, I'm importing a few of my Office documents (Word docs and Excel spreadsheets so far) to see what happens. I've run into a problem with Numbers and hope someone can help. This problem isn't about an import issue, it seems to be a problem with trendlines in Numbers.
    I have created a scatter chart with a logarithmic X axis, linear Y axis, and a logarithmic trendline. A log trendline on this chart should be a straight line. The trendline equation is correct and I can create and plot a second series using the equation but the trendline plotted by Numbers is nowhere near correct. The trendline is plotted as if the X axis is a linear scale, which it is not. In fact, if I change X to a linear scale, the trendline looks exactly the same as before (but is now correct).
    Any ideas, am I doing something wrong?

    For the original problem, it is easy to create a simple 5 datapoint logarithmic chart with a trendline by just making up some numbers. I can't send you my data because it is company proprietary. I put in feedback to Apple, I'm sure a bug report will go in soon from someone else with the same problem. I think I'll drop it at this time. I can do without the trendline plots for a while as long as I can get the equations (which seem to be correct).
    On the issue of trendlines being non-equivalent when swapping the X and Y axis, that is not a bug so no action is required.
    Thanks.

  • How to Make a Line of Best Fit/Best Fit Line/Trendline in iWork Numbers '09

    I'm not sure if this is well-known or has been answered elsewhere already, but multiple Google searches have not shown this solution on how to create a line of best fit in Numbers '09 (there is another method that involves drawing a line yourself, but this is much easier and more accurate).
    I stumbled across this trying the above self-draw technique and got so excited I wanted to post the technique. So here is what you do:
    1) Type out your X and Y data
    2) Select the data and select Charts, then select the Scatter Plot
    3) Open up Inspector and select the Chart tab
    4) Select the "Series" tab below the picture of the Scatter Plot and the "Chart Colors..." button
    5) At the bottom of the Inspector window, open the "Advanced" arrow
    6) Select the "Trendline" tab and select the "Linear" trendline from the drop-down bar
    That's it! You can even select the options to show the line equation or the R-squared value!
    Here is a picture of the selected options and what your graph should look like (check that nice R-squared value!).
    http://i.imgur.com/AvfPv.png
    I hope this helps and hope it moves up to the top of the Google search page for this feature.

    Hi Asclepius37,
    Why not just search "trend" or "trendline" in the Numbers '09 User Guide?
    That would take you to page 149 of the guide and the article "Showing Trendlines in Charts," which lists a set of instructions very similar to those in your post.
    The Numbers '09 User Guide and the iWork Formulas and Functions User Guide are searchable pdf files, and may both be downloaded through kinks in the Help menu in Numbers. Both are excellent resources to have on hand.
    Regards,
    Barry
    PS: Searching "best fit" will return zero results, but "best" or "best-fit" will get you to the same article.
    B

  • Numbers hangs consistently upon adding a trendline.

    As the subject says. I'm making a scatter plot, all is well. Nice and easy to make. But, as soon as I add a trendline to it, Numbers freezes, then seemingly corrupts the file, making it hang every time I open it again.
    What can I do... besides download Open Office and use that instead?

    Well, I figured it out for myself. Permissions did nothing, nor did the preferences file.
    However, it turns out Numbers was getting stuck with my trendline because one of the values was a gigantic outlier. Think most values plotting below 1.0, and this one plotting at 140.
    Thanks for the help, though. Much appreciated!

  • How do I add a linear slope equation (y-intercept form) to a graph in the latest version of numbers?

    I recently spent a lot of time trying to figure out how to add a linear slope equation to the best fit line of a scatterplot graph in numbers, which was a requirement for a chemistry lab report I was working on. After failing to figure it out on my own or find any relevant info on the internet, I had to copy/paste my data into excel and do it from there. Does anybody know how I can do this in numbers? Obviously excel works just fine but I like the aesthetics and the simpler formatting options of the graphs that I get using numbers.

    The option to show the linear best fit equation is in the Series Format pane under Trendlines.
    Jerry

  • How to create a chart using x-y correlation line plotting and trendline?

    Hi everyone,
    I am a college student and I opted to use iWork instead Microsoft Office, which has been wonderful software until this semester (iWork '08). Currently, I am taking some science classes, which requires me to graph simple function using "excel"; since I have Numbers, I attempted to graph my homework using such software. However, it was a little disappointing because I could not find x-y correlation line plotting, trendline, or simple curve fitting in Numbers.
    Is Numbers able to graph in such way? If yes, what is the best approach to find such tools?
    Any help will be truly appreciated.
    M
    Message was edited by: MacBook it works

    Plotting a function, eg y = 2x^2 + 3x + 2 or similar, in numbers or excel / appleworks / open office is not directly possible. The indirect way to do it is to build a spreadsheet put the values of x in one column and the formula to calculate the values of y in another and use these two columns to produce a chart. As you are plotting the function via calculated data (rather than trying to find a relationship by plotting observed data) trend line or curve fitting seems unnecessary.
    You can plot observed data and produce a scatter chart in Numbers, but it will not produce a trendline for you. You could calculate the parameters of the trendline, there are a number of shareware products that will do this. See http://www.apple.com/downloads/macosx/mathscience/indexabc.html. Once you calculate the trendline you could use the technique described above to plot it.
    You can plot a function directly using Grapher which lives in the Utilities folder. It can also be used to plot data sets and do simple curve fitting.
    Hope this helps, but as always to solve a problem you have to clearly define it first.

  • Line of Best Fit/Trendline

    As part of my Physics class we need to graph data that can only be displayed using a line of best fit (AKA a Trendline) - I can make any graph fine on Numbers but I am at a loss on how to make a trendline.
    Could you please aid me in my search to create a Trendline?
    Thanks,
    Jean-Paul J
    Message was edited by: Jean-Paul J

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  • Remove one segment of line connecting points in a trendline chart?

    I have a linear trendline plotted where the data points for the first 19 values lie on either side of the trendline. These are joined by a dashed line. I want to keep that line intact.
    The last 9 points lie along the trendline and are indistinguishable from it. That's fine, too.
    I want to remove just the segment of the dashed line running from the last distinguishable point to the first indistinguishable one. Breaking the 28 point dataset into two sets isn't an option since I need all 28 to produce the trendline. The trendline is the reason for the chart.
    Anything I can do to remove that segment of dashed line? Wite Out isn't an option.
    Thanks for any ideas.

    Badunit--
    That is really clever, and it should work. I really appreciate your response.
    You've understood the problem. I have a trendline derived from the cluster of data points with one point for each of 20 years (1991-2010). My requirement is a chart showing both those 1991-2010 points and the trendline (with precision) from 1991 extended to 2020. Since the known values stop at 2010, and since Numbers can't extend the trendline without a workaround, I received help (from you, as a matter of fact) last year on this Forum finding a way to plot the line (essentially by trial and error for the future points). To check my values from last year, I tried out Excel for Mac 2004 and found Excel provided the numerical values through 2020. I plugged them into my Numbers table and life is good.
    The objective in this post was to remove the connector joining the 2010 point to the trend line value point for 2011. The 2011-2020 points don't need to be visible--only the trendline they generate.
    Your solution should result in my generating the trendline using my full set of 1991-2020 points. I suppose the points along it from 2011-2020 could be made invisible while the trendline stroke and color could be "robust."
    A second series, the set of points for 1991-2010, will be visible and connected. If the first series of points is made invisible, there won't be any double vision problems for 1991-2010.
    Much appreciated. I'll give it a try. [ I went into the detail above since someone else may encounter similar problems. FYI, your previous help was on 22 July 09].
    Terry

  • Numbers 3.1 restricting the period for moving average trend lines

    Numbers 3.1 is restricting the period I can specify for a moving average trend line for a scatter plot series. The max is 6. This limitation was not present in the previous version of Numbers.
    Charts imported from the previous version retain larger periods, but there is no way I can see to specify periods >6 for any new series. Is there a way to allow a period >6? That is clearly necessary for many applications.
    Thanks.

    Hi Bill,
    Numbers 3.1
    If you want a 14 day moving average over the prior 14 days, the formula in C10 is
    =AVERAGE(B2:B15) (and Fill Down)
    The formula will eventually run out of cells. Hence the red error triangles.
    Plotting columns A, B and C:
    X axis is Day (column A)
    Blue circles and blue line are Actual Y (column B and as expected, they jump around).
    Black circles and black line are calculated moving averages on a 14 day period (column C)
    Red line is Numbers Trendline (Moving Average, Period 6). How it predicts into the future (Moving Average over 6 days) I have no idea.
    I would more trust a calculated moving average, because I know what it is calculating.
    Regards,
    Ian.

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