Interpreting trend using parallel boxplot

[Olanike]

Hi All,

I am using proc box plot to determine a trend in a multi-yr nutrients' study. I have attached the results of the parallel box plot across the years.

Please how do I  interprete these two figures (viz-a-viz the trend across the years).

Thanks.

[Reeza]

Box plots show:

Distribution, measures of centres and outliers. So pick each of those metrics and compare them over the years. 

How has the distribution changed over the years? Did it get more variable? Or did it get less variable? Did it change at a consistent rate or did it vary, i.e. get high then low. 

Then rinse and repeat for each of your metrics. 

Hope that helps you get started.