Suppose X ∼ Binom(n, p). Show that E[X] = np.

A First Course in Probability (10th Edition)
10th Edition
ISBN:9780134753119
Author:Sheldon Ross
Publisher:Sheldon Ross
Chapter1: Combinatorial Analysis
Section: Chapter Questions
Problem 1.1P: a. How many different 7-place license plates are possible if the first 2 places are for letters and...
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Suppose X ∼ Binom(n, p). Show that E[X] = np.

Expert Solution
Step 1: Given information

Suppose X tilde text Binom end text open parentheses n comma space p close parentheses

Its probability mass function is defined as,

P open parentheses X equals x close parentheses equals open curly brackets table row cell open parentheses table row n row x end table close parentheses space p to the power of x space q to the power of n minus x end exponent space space semicolon x equals 0 comma space 1 comma space 2 comma space. space. space. space. space comma space n space end cell row cell space space space space space space space space space 0 space space space space space space space space space space space space space space space semicolon space text otherwise end text end cell end table close

Where,

q equals 1 minus p

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