Table 3

Classification table with sensitivity and specificity obtained by 10-fold cross validation, used to test the decision tree for joint effusion shown in fig 2

Actual class	Predicted class		Actual total
Actual class	No effusion	Effusion	Actual total
Sensitivity = 71.6%, specificity = 43.2%; LR+ 1.26.
No effusion	146	192	338
Effusion	74	187	261
Predicted total	220	379	599