A-level Statistics Edexcel 2020 Q5 Explained WITHOUT Conditional Probability - Normal Distribution

In this video I go through an A-level maths question from Edexcel. We are asked to conduct a hypothesis test with the normal distribution, and then find the median for the new (refined) model. Part d) is fairly difficult at first and the explanation in the mark scheme jumps straight to using conditional probability, which isn't necessarily obvious. In this video I explain the solution in a different way (using the same maths!). Part d) begins at 11:15.