Seasonal pattern analysis

Hello everyone,

I want to do a seasonal pattern analysis of a disease incidence. I have the
data on incidence number in each month for 3 years. I saw a good package
called "season" in R. But it looks like it does the analysis for monthly,
weekly or daily fashion. But I need to do the analysis for summer, winter,
spring and autumn. Can anybody give me some help on choosing most suitable
package to do this?

Thanks much
ARshad

:jak

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