Entrance examination HEC ESCP ESSEC 25:mathématiques 2.
In this article you'll find suggested answers for the Maths 2 Maths approfondies subject of the HEC ESCP ESSEC 2025 competitive entrance exam.
A fairly boring problem for statisticians, revolving around Student's law and the \(\chi^2\) law.
In the course of the problem, we also demonstrate certain stability properties of the normal distribution, for example if \(X\hookrightarrow \mathcal{N}(0,1)\) and \(X\hookrightarrow \mathcal{N}(0,1)\) are independent, then \[ \begin{alignat*}{1} W &=\frac{X+Y}{\sqrt{2}}\\ Z &=\frac{X-Y}{\sqrt{2}}\\ \end{alignat*} \] are independent and follow a normal distribution \(\mathcal{N}(0,1)\).
Solution of problem set Maths 2 approfondies given on April 25th for the entrance exam 2025 of HEC ESSEC ESCP:
Find the problem statement here: