# Expected value and variance

**Question description**

A group of 20 people consisting of 10 men and 10 women is randomly arranged into pairs of 2 each. Compute the expectation and variance of the number of pairs that consist of a man and woman. Now suppose the 20 people consist if 10 married couples. Compute the mean and variance of the number if married couples that are paired together

## Tutor Answer

Brown University

1271 Tutors

California Institute of Technology

2131 Tutors

Carnegie Mellon University

982 Tutors

Columbia University

1256 Tutors

Dartmouth University

2113 Tutors

Emory University

2279 Tutors

Harvard University

599 Tutors

Massachusetts Institute of Technology

2319 Tutors

New York University

1645 Tutors

Notre Dam University

1911 Tutors

Oklahoma University

2122 Tutors

Pennsylvania State University

932 Tutors

Princeton University

1211 Tutors

Stanford University

983 Tutors

University of California

1282 Tutors

Oxford University

123 Tutors

Yale University

2325 Tutors