Question

Calculate Accuracy, Precision, Recall and F1 Score for the following Confusion Matrix on Water Shortage in Schools: Also suggest which metric would not be a good evaluation parameter here and why ?

Topic	Evaluation (project cycle)
Type	Long Answer Type
Class	10

Answer 1

The Confusion Matrix (Water Shortage in School)	Reality:1	Reality:0
Prediction : 1	75	5
Prediction : 0	5	15

	Reality:1	Reality: 0
Prediction: 1	75	5	80
Prediction: 0	5	15	20
	80	20	100

Calculation: 

Accuracy

Accuracy is defined as the percentage of correct predictions out of all the observations 

Accuracy = Correct Predictions / Total Cases * 100%

Accuracy = (TP + TN) / (TP + TN + FP + FN ) * 100%

Where True Positive (TP), True Negative (TN), False Positive (FP), and False Negative (FN).

= (75+15) / (75+15+5+5) = (90 / 100) =0.9 

Precision: 

Precision is defined as the percentage of true positive cases versus all the cases where the prediction is true.

Precision = True Positive / All Predicted Positives *100%

Precision =(TP/TP+FP) *100%

= 75 / (75+5) 

= 75 /80

= 0.9375

Recall:

It is defined as the fraction of positive cases that are correctly identified.

Recall= True Positive / True Positive + False Negative 

Recall= TP/TP+FN

= 75 / (75+5) = 75 /80 = 0.9375

F1 Score:

F1 score is defined as the measure of balance between precision and recall. 

= 2 * ((0.9375 *0.9375) / (0.9375+0.9375)  

F1 Score = Precision*Recall/Precision + Recall

Therefore

= 2 * (0.8789 / 1.875) 

= 2 * 0.46875 = 0.9375  

Accuracy= 0.9% Precision= 0.9375% Recall= 0.9375% F1 Score= 0. 

Here precision, recall, accuracy, and f1 score all are the same 

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Study more about Evaluation at Evaluation Class 10