Checkout times in a grocery store follow the exponential distribution with a mean time of 6.5 minutes.What is the probability that the checkout time (T)for the next customer will be less than 5 minutes?
A)0.537
B)0.463
C)0.257
D)0.950

Question

Quizplus · Accepted Answer

The exponential distribution is given by the formula $P(T < t) = 1 - e^{-\lambda t}$, where $\lambda = \frac{1}{\text{mean}}$. Here, the mean checkout time is 6.5 minutes, so $\lambda = \frac{1}{6.5}$. For $t = 5$ minutes, $P(T < 5) = 1 - e^{-\frac{5}{6.5}} \approx 0.537$.

Checkout Times in a Grocery Store Follow the Exponential Distribution