The discrete random variable X is the number of students that show up for Professor Smith's office hours on Monday afternoons. The table below shows the probability distribution for X. What is the probability that fewer than 2 students come to office hours on any given Monday? $$\begin{array} { l c c c c r }
X & 0 & 1 & 2 & 3 & \text { Total } \
P ( X ) & 40 & 30 & 20 & 10 & 1.00
\end{array}$$
A).10
B).40
C).70
D).90

Question

The discrete random variable X is the number of students that show up for Professor Smith's office hours on Monday afternoons. The table below shows the probability distribution for X. What is the probability that fewer than 2 students come to office hours on any given Monday? $$\begin{array} { l c c c c r } 
X & 0 & 1 & 2 & 3 & \text { Total } \
P ( X ) & 40 & 30 & 20 & 10 & 1.00
\end{array}$$
A).10
B).40
C).70
D).90

Quizplus · Accepted Answer

The probability that fewer than 2 students come to office hours is the sum of the probabilities that 0 or 1 student comes, which is 40% + 30% = 70%.

The Discrete Random Variable X Is the Number of Students X0123 Total P(X)403020101.00\begin{array} { l c c c c r } X & 0 & 1 & 2 & 3 & \text { Total } \\P ( X ) & 40 & 30 & 20 & 10 & 1.00\end{array}XP(X)​040​130​220​310​ Total 1.00​

The Discrete Random Variable X Is the Number of Students $\begin{array} { l c c c c r } X & 0 & 1 & 2 & 3 & \text { Total } \\P ( X ) & 40 & 30 & 20 & 10 & 1.00\end{array}$