Confusion matrix instances interpretation

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Confusion matrix instances interpretation

Getch Rch

Dear sir,
Currently I'm using Weka 3.8.3 for classification study. I have used 398,773 instances with 66% for training and 34% for testing. During this train test split Weka sets the number of training instances to 135582.5. Finally when I look into the confusion matrix of a classifier the number of true-negative instances equals 44544.2. My question is what are the fractional number of instances like 0.5 in train test split and 0.2 in confusion matrix result?

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Re: Confusion matrix instances interpretation

Eibe Frank-2
Administrator
It seems that your data must have (non-integer) instance weights? Those are defined by curly braces at the end of the row of data values corresponding to an instance in the ARFF file.

Cheers,
Eibe

On Mon, Jan 6, 2020 at 4:58 PM Getch Rch <[hidden email]> wrote:

Dear sir,
Currently I'm using Weka 3.8.3 for classification study. I have used 398,773 instances with 66% for training and 34% for testing. During this train test split Weka sets the number of training instances to 135582.5. Finally when I look into the confusion matrix of a classifier the number of true-negative instances equals 44544.2. My question is what are the fractional number of instances like 0.5 in train test split and 0.2 in confusion matrix result?
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