Page 317 - AI Ver 1.0 Class 10
P. 317
Task
Now after understanding the concept of Accuracy, according to you how much percentage of accuracy is reasonable
to show good performance?
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In the above Scenario of Board Exams prediction:
Let’s assume
True Positives = 0
True Negatives = 90
Total cases = 100
Therefore:
Accuracy becomes: ((90 + 0) / 100) *100 = 90%
This is a fairly high accuracy for an AI model.
The model predicts that there are NO BOARD EXAMS. But in reality, there are 10% chances of Board exams to
be conducted. In this case, for 90 cases the model will be right but for 10 cases in which there are chances of
conducting Board Exam but still model predicted NO BOARD EXAMS.
But this parameter is useless for us as the actual cases which are 10 in our above example are not taken into
account.
Hence, there is a need to look for another parameter which takes into account the situation as in the above
example.
Precision
Precision is the percentage of True Positive cases and All Predicted Positive Cases.
Its formula is:
True Positive
Precision = × 100%
All Predicted Positives
TP
Precision = × 100%
TP + FP
Where,
All Predicted Positive = True Positive + False Positive
Evaluation 315

