estimation prediction error=measured value-predicted value measured value× 100 .
example for estimation prediction error
to find the heart disesase lets take the data of the person’s chestpain,bloodcirculation,blocked arteries,weight to work on this data we will use the knn algorithm/vectormachines and many more machine learning methods to identify which method is suitable the cross validation will suggest the best method like train,test methods.in this example we diivided the data in to 4blocks so this is called four cross validation in this way we can find the exact value using the data.