How it works...

This section explains how the array is validated and constructed for optimal future use within the neural network.

1. The new mean of the height should be 0 and the standard deviation should be 1. This can be seen in the following screenshot:

2. This is confirmation of a normalized dataset, as it includes a mean of 0 and a standard deviation of 1.
3. The original data_array is no longer useful for a neural network because it contains the original, non-normalized, input values for height, weight, and gender.
4. Nonetheless, with a little bit of numpy magic, data_array can be restructured to include the normalized height and weight, along with gender.  This is done with numpy.stack().   The output of the new array, data_array, can be seen in the following screenshot: