Confusion matrix
Definition taught in Estimating error rates, part of Statistical learning
Confusion matrix
| Type | Definition |
| Taught in | Estimating error rates |
| Part | Statistical learning |
| Questions using it | 2 |
A confusion matrix has, in position (i,j), the number of observations of true class i that the classifier predicted as class j. Dividing the matrix by the number of observations in the test set, the sum of the off-diagonal elements is \widehat{\mathrm{Err}}. Dividing row g by its own total, the sum of that row excluding the diagonal element is \widehat{\mathrm{Err}}_g.
Used in
- Taught in Estimating error rates, where the derivation and examples are.
- Questions that use it (2) — A confusion matrix · What an accuracy table does and does not say
- All 7 questions on Estimating error rates
See also
A held-out test set · Sensitivity and specificity · Fixed-rule error · Apparent error · Leave-one-out cross-validation · -fold cross-validation · Bootstrap error and the correction · Jackknife bias and standard error