what to test on validation set why is a data validation a test what is the test of the model set what to do with a test set which is the best use of training and validation data? what is the purpose of the testing data where do you refine a model what to do when you use test data what data is tested for in validation what to do when model training is done what is the test data for a training and validation? how to validate an external model what is model training? what to do with testing data what do you do with testing data when can you test on the testing set do you test with testing sets when to use testing set in a model how do i test a training model which data is used to train your model?