And just so you know where we're going with this, the whole point of this is so that we can eventually do some inferential statistics about differences of means.
Everything we do, or almost everything we do in inferential statistics, which is essentially making inferences based on data points, is to some degree based on the normal distribution.
" They're extremely rational and they're much better in some ways at doing inferential learning" – using patchy information to make accurate generalisations about a messy world – " than any other creature that we know of."