Posible mistake in Quiz 1 solutions

Posible mistake in Quiz 1 solutions

by Mario Fernández Blanco -
Number of replies: 1

Greetings,

While reviewing the proposed solutions to Quiz 1, I came across some of them that seemed to be wrong.

For example, in this question, the precision of the system is said to be 0.34. 

Image of the exercise of the quiz

However, if we use the formula Precision=True Positives​/(True Positives+False Positives) we get 633 / (633 + 72), which is 0.9. If the result is not wrong, where does it come from?


The same happens for the following exercise regarding recall:

Image from the quiz

Maybe I have completely missunderstood the exercise, but shouldn't the solutions be other numbers?


Thank you in advance

In reply to Mario Fernández Blanco

Re: Posible mistake in Quiz 1 solutions

by Jean-Cédric Chappelier -
Hello!
What is the purpose of using precision and recall?
When do we use them? to measure what?

With your measures, what would be the score of a system classifying everything as negative (the most represented class)?

I hope this helps.
If not, I'll be happy to deepen further.