# [R] comparition of occurrence of multiple variables between two dataframes

Céline Lüscher c-luescher at hispeed.ch
Tue Sep 12 12:27:35 CEST 2017

```Hi everyone, I need your help to solve a problem with occurrence and two dataframes.
I have an excel table of 15200 lines. Each line correspond to a tree analyzed for its structures. I have all the structures in columns (48 structures). The occurrence of these structures has been counted on every tree. For example, the tree 12607 has 3 structures CV11, 1 structure IN12 and none (0) of the rest of all the other structures. The very last column is the value given to the tree, according to the structures found on it (each structure giving a number of point to the tree by its presence on it).
The question is: Are there some structures, or combination of structures, which give a high value to the tree ? Of course, according to the value of each structure, we can see which one has a higher value than the others (ex: structure CV11 has a value of 15, structure IN12 has a value of 4). But what I want to know is, if we take all the trees having a final value higher than 100 (we create a new dataframe "data100"), and we compare with the trees having a final value under 100 (we create another dataframe "data0"), can we find a significant difference in the number and occurrence of structures found on these trees? And which structure is related to trees with a higher value than 100 ?
For now, I have only a visual answer to the question. I did two boxplot of the data100 and data0, and I have seen some différences : 2 structures are only found in the data100, which can be caracteristic of a final value higher than 100. The problem is that I’m looking for a test to prove this.
If you have any idea or proposition for solving this problem.. it will be great!
Best wishes,
C.

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