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Thread: ANOVA - floral longevity, seeking feedback on tests performed

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    ANOVA - floral longevity, seeking feedback on tests performed




    I have done my statistical analysis and would appreciate any feedback to say if my tests are appropriate. If not, what tests would you recommend? I am a biology honours student researching treatment of flowers for longevity.

    The time from the flower fully opening to the start of senescence (death of the flower) was measured with six replicates. This experiment is not yet complete (i.e. not all flowers have died yet, so the means will increase on most groups).

    Please see first plot of days to senescence vs treatment. Mean +/- standard error is shown for six replicates.

    I did the following tests on the whole data set:
    One-way ANOVA, p = 0.009
    Leveneís test of Homogeneity of Variance, p = 0.006
    Games-Howell post hoc (due to non-homogeneity of variance)
    - STS compared with D, p = 0.023
    - B compared with D, p = 0.071
    - A compared with D, p = 0.075

    The mass of each flower was measured daily, and the percentage gain or loss calculated based on the flower mass on day 0 (the day the flower fully opened).

    Please see second plot of flower mass vs day number. Mean +/- standard error shown for six replicates. Treatment A is the top curve, treatment D is the bottom curve. For visibility Iíve only shown two of the six curves, but one-way ANOVA and the Games-Howell post-hoc test was performed on the whole data set for each day individually. P-values less than 0.05 returned from Games-Howell were found on days 9, 10, 11 and 12 when comparing treatment A and D.

    Analysis was done in PSPP.

    Thank you for taking the time to read this post. Any comments on if you think these tests were appropriate or not would be appreciated.
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    Re: ANOVA - floral longevity, seeking feedback on tests performed

    Two alternative analyses would be a longitudinal repeated measures ANOVA as well as a survival analysis. These analyses would use more of the available data.

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    Re: ANOVA - floral longevity, seeking feedback on tests performed


    Thanks Miner. I will look into the two analyses you suggested.

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