Bayes Linear Statistics is a type of mathematical formula that helps to calculate the chance of something happening. It is based on the idea that if you know two things about something, you can use these two things to figure out the third. To understand this better, think about a coin. If you flip a coin, you know that it is either going to be heads or tails, so there is a 50% chance that it will be heads and a 50% chance that it will be tails. By putting in the two pieces of information (the two sides of the coin), you can use Bayes Linear Statistics to figure out what the chances are of heads or tails.