[R] Counting things
Noah Silverman
noah at smartmediacorp.com
Wed Aug 5 05:40:15 CEST 2009
I've completed an experiment and want to summarize the results.
There are two things I like to create.
1) A simple count of things from the data.frame with predictions
1a) Number of predictions with probability greater than x
1b) Number of predictions with probability greater than x that are
really true
In SQL, this would be,
"Select count(predictions) from data.frame where probability > x"
"Select count(predictions) from data.frame where probability > x and
label ='T' "
How can I do this one in R?
2) I'd like to create what we call "binning". It is a simple list of
probability ranges and how accurate our model is. The idea is to see
how "true" our probabilities are.
for example
range number of items mean(probability) true_accuracy
100-90% 20 .924 .90
90-80% 50 .825 .84
80-70% 214 .75 .71
etc...
It would be really great if I could also graph this!
Is there any kind of package or way to do this in R
Thanks!
-N
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