Keyword Question - Which is Better?

I have two words that I am considering for my description and I have the Search Scores and Chance Scores but I am not understanding something. I have the same Search Score for both words at 52. My chance score is 59 and 71. The weird thing is that I am ranked for the word with the lower chance score with the same number of available apps. Does that mean I should use the 59 word that is ranked or the 71 unranked word?

Thank you very much for all the help.!

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