anova analysis on factors...

Hi all,

If we wanted to study the effect on the mean of the hourly data based on
the hours within a day...

and we wanted to do Anova analysis...

We have two choices:

Please see below:

Why are these two approaches giving very different p-values? And which one
shall I use?

Thanks a lot!

1. treating the hours as double/floating numbers:


anova(lm(hourlydata~as.double(hours_factors)))

Df Sum Sq Mean Sq F value Pr(>F)

as.double(hours_factors) 1 0.0002 0.00019876 1.3425 0.2466

Residuals 14868 2.2013 0.00014806

2. treating the hours as factors:



anova(lm(hourlydata~hours_factors))

Df Sum Sq Mean Sq F value Pr(>F)

hours_factors 9 0.00077 8.5979e-05 0.5806 0.8142

Residuals 14860 2.20072 1.4810e-04

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