问一道题：NO.PZ2016062402000003-有问必答-品职教育专注CFA ESG FRM CPA 考研等财经培训课程

NO.PZ2016062402000003 问题如下 The joint probability stribution of ranm variables X anY is given f{(x,y)}=k * x * y for x = 1,2,3, y = 1,2,3, ank is a positive constant. Whis the probability thX+Y will excee5? 1/9 1/4 1/36 Cannot termine The function x*y is scribein the following table. The sum of the entries is 36. The scaling factor k must suththe totprobability is 1. Therefore, we have k=1/36. The table shows one instanwhere X+Y 5，whiis x=3, y=3. The probability is p = 9/36 = 1/4.中文解析这道题目考察的是联合概率分布。符合题目条件的只有一种情况（X=3，Y=3），但要想求概率，就得首先求到联合概率分布公式中的k。题目里说，它的联合概率分布是F(x,y)=k*x*y，x可以取3种，y可以取3种，所有总共有9种可能性。其中，每一种可能性的概率都为x*y*k。将9种可能性的概率相加，它的概率之和为36k。因为所有情况的概率之和为1，所以有36k=1，所以k=1/36。最后P(X+Y 5)= P(X=3, Y=3) = 9k =1/4 为什么不是1/9?

2024-04-07 15:55 1 · 回答

NO.PZ2016062402000003问题如下The joint probability stribution of ranm variables X anY is given f{(x,y)}=k * x * y for x = 1,2,3, y = 1,2,3, ank is a positive constant. Whis the probability thX+Y will excee5?1/9 1/4 1/36 Cannot termine The function x*y is scribein the following table. The sum of the entries is 36. The scaling factor k must suththe totprobability is 1. Therefore, we have k=1/36. The table shows one instanwhere X+Y 5，whiis x=3, y=3. The probability is p = 9/36 = 1/4.中文解析这道题目考察的是联合概率分布。符合题目条件的只有一种情况（X=3，Y=3），但要想求概率，就得首先求到联合概率分布公式中的k。题目里说，它的联合概率分布是F(x,y)=k*x*y，x可以取3种，y可以取3种，所有总共有9种可能性。其中，每一种可能性的概率都为x*y*k。将9种可能性的概率相加，它的概率之和为36k。因为所有情况的概率之和为1，所以有36k=1，所以k=1/36。最后P(X+Y 5)= P(X=3, Y=3) = 9k =1/4 解答了一年，还是不明白什么意思！什么1个K，36个K？能不能来个助教把它讲明白了

2024-04-03 14:44 1 · 回答

NO.PZ2016062402000003 问题如下 The joint probability stribution of ranm variables X anY is given f{(x,y)}=k * x * y for x = 1,2,3, y = 1,2,3, ank is a positive constant. Whis the probability thX+Y will excee5? 1/9 1/4 1/36 Cannot termine The function x*y is scribein the following table. The sum of the entries is 36. The scaling factor k must suththe totprobability is 1. Therefore, we have k=1/36. The table shows one instanwhere X+Y 5，whiis x=3, y=3. The probability is p = 9/36 = 1/4.中文解析这道题目考察的是联合概率分布。符合题目条件的只有一种情况（X=3，Y=3），但要想求概率，就得首先求到联合概率分布公式中的k。题目里说，它的联合概率分布是F(x,y)=k*x*y，x可以取3种，y可以取3种，所有总共有9种可能性。其中，每一种可能性的概率都为x*y*k。将9种可能性的概率相加，它的概率之和为36k。因为所有情况的概率之和为1，所以有36k=1，所以k=1/36。最后P(X+Y 5)= P(X=3, Y=3) = 9k =1/4 反复看了解答，还是没明白为什么不是1/3*1/3=1/9

2024-02-11 21:48 1 · 回答

NO.PZ2016062402000003 问题如下 The joint probability stribution of ranm variables X anY is given f{(x,y)}=k * x * y for x = 1,2,3, y = 1,2,3, ank is a positive constant. Whis the probability thX+Y will excee5? 1/9 1/4 1/36 Cannot termine The function x*y is scribein the following table. The sum of the entries is 36. The scaling factor k must suththe totprobability is 1. Therefore, we have k=1/36. The table shows one instanwhere X+Y 5，whiis x=3, y=3. The probability is p = 9/36 = 1/4.中文解析这道题目考察的是联合概率分布。符合题目条件的只有一种情况（X=3，Y=3），但要想求概率，就得首先求到联合概率分布公式中的k。题目里说，它的联合概率分布是F(x,y)=k*x*y，x可以取3种，y可以取3种，所有总共有9种可能性。其中，每一种可能性的概率都为x*y*k。将9种可能性的概率相加，它的概率之和为36k。因为所有情况的概率之和为1，所以有36k=1，所以k=1/36。最后P(X+Y 5)= P(X=3, Y=3) = 9k =1/4 不懂为什么是1/36，函数不是k*x*y？x有3种可能性；y有3种可能性，不应该是1/9吗？

2023-02-06 23:58 2 · 回答

NO.PZ2016062402000003 问题如下 The joint probability stribution of ranm variables X anY is given f{(x,y)}=k * x * y for x = 1,2,3, y = 1,2,3, ank is a positive constant. Whis the probability thX+Y will excee5? 1/9 1/4 1/36 Cannot termine The function x*y is scribein the following table. The sum of the entries is 36. The scaling factor k must suththe totprobability is 1. Therefore, we have k=1/36. The table shows one instanwhere X+Y 5，whiis x=3, y=3. The probability is p = 9/36 = 1/4. k等于1/36不是x*y的概率吗，x+y和这个k有什么关系

2022-04-26 15:07 1 · 回答

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