The time between buses arriving at the stop follows an exponential distribution with a mean of 26 minutes.
To find the probability of waiting at least 4 minutes for the bus, we can use the cumulative distribution function (CDF) of the exponential distribution:
P(waiting at least 4 minutes) = 1 - P(waiting less than 4 minutes)
The probability of waiting less than 4 minutes can be calculated using the CDF:
P(waiting less than 4 minutes) = 1 - e^(-4/26) ≈ 0.146
Therefore, the probability of waiting at least 4 minutes for the bus is:
P(waiting at least 4 minutes) = 1 - 0.146 ≈ 0.854
So the probability of having to wait at least 4 minutes for the bus is about 85.4%.