Chapter 2 Section 2 Question 7

Question

Suppose a university is composed of 55% female students and 45% male students. A student is selected to complete a questionnaire. There are 25 questions on the questionnaire administered to a male student and 30 questions on the questionnaire administered to a female student. If X denotes the number of questions answered by a randomly selected student, then compute $P(X = x)$ for every real number x.

Answer

Author: Mohammad-Ali Bandzar| Date:Oct 14 2020

Probability that 25 questions are answered: $$P(X=25)=P(male)=0.45$$ Probability that 30 questions are answered: $$P(X=30)=P(female)=0.55$$ Otherwise:

$P(X=x)=0$ for all $w\notin\{25,35\}$

Probability that 25 questions are answered: $$P(X=25)=P(male)=0.45$$ Probability that 30 questions are answered: $$P(X=30)=P(female)=0.55$$ Otherwise:

$P(X=x)=0$ for all $w\notin\{25,35\}$