The number of customers in a line at a supermarket express checkout counter is a random variable with the following probability distribution.

$\begin{array} { c | c | c | c | c | c | c }
\boldsymbol { x } & 0 & 1 & 2 & 3 & 4 & 5 \
\hline \boldsymbol { P } ( \boldsymbol { x } ) & 0.08 & 0.26 & 0.32 & 0.16 & 0.11 & 0.07
\end{array}$

Find the probability that there are fewer than four people in line.
A) 0.18
B) 0.82
C) 0.11
D) 0.93

Question

The number of customers in a line at a supermarket express checkout counter is a random variable with the following probability distribution.
 
$\begin{array} { c | c | c | c | c | c | c } 
\boldsymbol { x } & 0 & 1 & 2 & 3 & 4 & 5 \
\hline \boldsymbol { P } ( \boldsymbol { x } ) & 0.08 & 0.26 & 0.32 & 0.16 & 0.11 & 0.07
\end{array}$

Find the probability that there are fewer than four people in line.
A) 0.18
B) 0.82
C) 0.11
D) 0.93

Quizplus · Accepted Answer

To find the probability that there are fewer than four people in line, we need to add the probabilities of having 0, 1, 2, or 3 people in line.
$$ P(X<4) = P(X=0) + P(X=1) + P(X=2) + P(X=3)$$
$$ P(X<4) = 0.08 + 0.26 + 0.32 + 0.16 $$
$$ P(X<4) = 0.82 $$
Therefore, the correct choice is B.

The Number of Customers in a Line at a Supermarket