Solved by vmirly1 in post #2 
              
              
                The mean and std are the values that will be used in this equation: X' = (X-mean)/std. 
It’s optional whether you want to calculate exactly the mean and std of your training data or just use these generic values of (0.5, 0.5, 0.5). But, it’s very common practice to just use generic values mean=(0.5,…