Why 0 mean is desirable for data in neural networks? [duplicate]

It is suggested to normalize data as 0 mean and 1 variance. Also, TanH considered better than Sigmoid activation function as it has 0 mean. Why 0 mean is important?

• $\tanh(0)=0$ but that's not the same thing as having a mean of zero. Suppose $x$ is uniformly distributed on $[-2,-1]$; in this case, $\mathbb{E}(\tanh(x)) < 0$. – Sycorax says Reinstate Monica Jul 4 at 19:05