Skip to content
Competitive Stats
Q8Section I (Objective (Q1–Q80))8 of 79

Distribution Theory — expectation of reciprocal sum of squared normals

Consider the following for the next four (4) items that follow: Let X1,X2,X3,…,X7X_1, X_2, X_3, …, X_7 be iid random variables, each having the N(0,1)N(0,1) distribution. What is E(1X12+X22+X32+X42)E\left(\frac{1}{X_1^2+X_2^2+X_3^2+X_4^2}\right) equal to?

Options

Pick an option to check your answer. In a mock test a wrong answer here costs 0.83 mark.