theliver wrote:>
> I'm currently doing simple, one way ANOVA using R.
>
> I'm analyzing a count based upon an Hour value (0-23) in which it
occurs.
> The count varies greatly over the entire day (usually with a range of 400
> or so), but certain hour groupings could be useful for later data
> processing.
>
> So I've loaded my data:
> data.nas <-
read.csv(file="simple.csv",head=TRUE,sep=",")
> [the file has headers of Center, MaxInst(which is the count im
> analyzing),Hour,X.ofCap]
>
> I've filtered it based on my needs
> data.ztl<-subset(data.nas,Center=="ZTL")
> data.ztlf<-subset(data.ztl,X.ofCap>97)
>
> which gives me everything I need to start breaking up the hours
>
> So I enter
>
> hours15t21.data.ztl<-subset(data.ztlf,Hour>14 & Hour<22)
>
> then
>
> aov.15t21.ztl<-aov(MaxInst~Hour, data=hours15t21.data.ztl)
>
> then
> summary(aov.15t21.ztl)
>
> and the output is
>
> Df Sum Sq Mean Sq F value Pr(>F)
> Hour 1 2745 2745 4.4879 0.03467 *
> Residuals 461 281939 612
>
> My problem is, since my data set has 7 different Hours, shouldn't the
> first DF be 6?
>
> I'm not ready to trust this output without knowing why DF is 1 and not
6.
>
>
Hour is being treated as a continuous variable, because R has no way of
knowing otherwise.
Try
hours15t21.data.ztl$Hour <- factor(hours15t21.data.ztl)
before running your aov() command.
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