In this question i would like to explain the difference between data set for example 100% data, ( train with 70% training, 15% test, 15% validation) , that is mean that using 85% of data for taring and after that select 15% from 85% for test ) finally used the 15% ( validation set). to validate the results . Note that the validation data set used only one time for validate but the test data used in training and testing.