The Weight of the Christmas Cake

At my daughters school they organize a charity event every year. There are all kinds of different foods, games and lotteries were you can spent money for the good cause. Since it is a british school the mandatory guessing of the Christmas cake weight must not be forgotten. 

In Agile and Scrum we praise ourselves about our estimation skills. It is not that we claim to be infallible. No, we also claim that laws in mathematics help us to be precise. One in particular is of interest: The law of large numbers.
The cake weighing proved to be change to put this practice under test.

This year we had 45 guesses and the weight from all the guesses is 3'742 kg. The real weight was 3'520 kg. The guessed weight is 94.1% accurate. Pretty impressive!