For t=1,..., n mini-batches,          Compute forward propagation on $X^{\{i\}}$                  In each hidden layer, use Batch Norm to replace $z^{(l)}$ with $\tilde{z}^{(l)}$           Use back propagation to compute $dW^{(l)}, d\gamma^{(l)},  d\beta^{(l)}$           Update parameters:                    $W^{(l)} = W^{(l)} - dW^{(l)}$                    $\gamma^{(l)} = \gamma^{(l)} - d\gamma^{(l)}$                    $\beta^{(l)} = \beta^{(l)} - d\beta^{(l)}$