← 返回数学题库
180概率困难derivationmedium

Hypergeometric Moments from an Urn

题目

An urn contains 20 balls: 8 red and 12 blue. You draw 5 balls without replacement. Let XX be the number of red balls drawn. Derive E[X]E[X] and Var(X)\text{Var}(X) using indicator random variables. Express each answer as an exact fraction.

解题计时

0:00

提交作答时记录,用于后续平均用时统计。

你的答案

第 1 项

第 2 项