Answer:
0.7788 = 77.88% probability that more than three customers arrive in 10 minutes
Step-by-step explanation:
Exponential distribution:
The exponential probability distribution, with mean m, is described by the following equation:
In which is the decay parameter.
The probability that x is lower or equal to a is given by:
Which has the following solution:
The probability of finding a value higher than x is:
In this question, we have that:
The time between arrivals of customers at an automatic teller machine is an exponential random variable with a mean of 4 minutes, and we have three customers, which means that
(a) What is the probability that more than three customers arrive in 10 minutes
This is P(X > 3). So
0.7788 = 77.88% probability that more than three customers arrive in 10 minutes