๐๐ก๐๐ง ๐ญ๐จ ๐๐จ ๐๐๐๐ญ๐ฎ๐ซ๐ ๐ฌ๐๐๐ฅ๐ข๐ง๐ ๐๐๐ญ๐๐ซ ๐ญ๐ซ๐๐ข๐ง ๐ญ๐๐ฌ๐ญ ๐ฌ๐ฉ๐ฅ๐ข๐ญ ๐จ๐ซ ๐๐๐๐จ๐ซ๐ ๐ญ๐ก๐ ๐ฌ๐ฉ๐ฅ๐ข๐ญ?
๐๐ง๐ฌ๐ฐ๐๐ซ: In general, feature scaling should be done after the split to avoid data leakage. [A THREAD>>>]
Let's take the example of standardization where we use the standard deviation of training data to scale the features. So to scale test data use the same standard deviation and scale test data (then calculate the standard deviation for testing data and use it.)