csat-suneung 2010 Q27b

csat-suneung · South-Korea · csat__math-science 3 marks Binomial Distribution Compute Expectation, Variance, or Standard Deviation

[Probability and Statistics] A certain math class has 10 groups, each consisting of 3 male students and 2 female students. When 2 people are randomly selected from each group, let $X$ be the random variable representing the number of groups in which only male students are selected. What is the expected value $\mathrm { E } ( X )$ of $X$? (Note: No student belongs to more than one group.) [3 points]
(1) 6
(2) 5
(3) 4
(4) 3
(5) 2

[Probability and Statistics] A certain math class has 10 groups, each consisting of 3 male students and 2 female students. When 2 people are randomly selected from each group, let $X$ be the random variable representing the number of groups in which only male students are selected. What is the expected value $\mathrm { E } ( X )$ of $X$? (Note: No student belongs to more than one group.) [3 points]\\
(1) 6\\
(2) 5\\
(3) 4\\
(4) 3\\
(5) 2

Paper Questions

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