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  1. #1
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    Finding average date

    I have a collection of daylilies, and each year I note when each cultivar blooms (mm/dd/yyyy). I have dates going back 10 to 15 years entered on my excel spreadsheet. I would like to be able to predict when each one will bloom again by calculating the average bloom date (mm/dd) for each cultivar. I just haven't been able to get the right formula to do this. Any suggestions?

  2. #2
    WS Lounge VIP sdckapr's Avatar
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    if your dates are in A1:A10000 and something like
    =Average(A1:A10000)
    Does not wor, you will have to explain what the issues are. Do you actually want a trendline? Would slope/intercept functions be more what you want for prediction?

    Perhaps you could attach a sample file with some of the data in it and explain what you have and want...

    Steve

  3. #3
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    Steve

    I'll try again. If I have this list of previous bloom dates, how can I find the month and day I could expect this plant to bloom again?

    Last edited by jackintx; 2011-12-04 at 16:21. Reason: Bad cut and paste

  4. #4
    Super Moderator RetiredGeek's Avatar
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    Jack,

    Something like this?
    Attached Images Attached Images
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    May the Forces of good computing be with you!

    RG

    PowerShell & VBA Rule!

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    jackintx (2011-12-05)

  6. #5
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    The years are irrelevant, as it flowers every year. It's the day and month you are interested in. Just format as DD/MM and use =MEDIAN(A1:A11); where data is in column A. This gives a date of 15 March. Or; Mode, on the other hand, gives a date of 20 Feb. (Most frequent date). Mean also gives 15 March. (Sum the dates and divide by number of dates).

    Just a thought; Why not use median or mean and plot a graph of days early or days late on the bloom? That will, over time, give you a better picture of what is going on. I did a line chart using your data and a Mean date of 15 March. (Attached). Needs a bit of fettling, but it's my bedtime, so I'm off.
    Attached Images Attached Images

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    jackintx (2011-12-05)

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