I calculate correct accuracy classification from confusion matrix as 1-c ,Sensiticity TP/(TP+FN) as SE = cm(2,2)/sum(cm(2,:)) and Specificity TN/(TN+FP) SP=cm(1,1)/sum(cm(1,:)) to a binary classification problem .Are these calculations right ?I use 10 fold cross validation in my data and i want calculate CA,SE ,SP of the test set which incudes 2 samples each time.Sometimes in test all are positives and classified as positives and then specificity is NaN .How can i cope this ?Im interested for the mean of these in 10 folds .
MATLAB: Sensitivity ,Specificity and Accuracy calculation from Confusion matrix
confusion matrixDeep Learning Toolboxneural networkpatternet
Related Solutions
Hi Giansu,
Let's understand the scatter plot and confusion matrix generated by Classification Learner App for k-fold cross-validation with an example of iris dataset having 150 samples and 5-fold cross-validation.
As we choose 5-folds, the app will partition the data into 5 disjoint sets or folds cross-validation. For each fold, the app trains a model using 4 folds as training data and remaining 1-fold (i.e. held-out fold) as validation data.
It means whenever we use k-fold cross-validation, all the 150 samples will be considered as validation data or held-out fold for once. For e.g., for first iteration 1st fold will be validation and remaining 4 folds will be training data and similarly for second iteration 2nd fold will be validation and remaining 4 folds will be training data.
Scatter plot: The each prediction shown in the scatter plot is obtained when that particular observation was a part of held-out fold or validation data while model was training.
Confusion Matrix: The confusion matrix depicts how correctly the model predicted the class of the observation when that particular observation was a part of held-out fold or validation data while model was training. Hence the values are integer in confusion matrix.
Accuracy: The accuracy is calculated for each k-fold and to calculate the accuracy for the model we do average.
Following are the scatter plot and confusion matrix which I got on iris data for 5-fold cross validation:
Hope it helps!
Your final belief is correct.
Best Answer