# Thread: Probability

1. ## Probability

Assume the the time required to download a file from the Internet is exponentially distrubuted with mean equal to 4 minutes. What is the probablity that a download will require at least 2 but not more then 4 minutes. (to five decimal places)?

2. Originally Posted by sweettea331
Assume the the time required to download a file from the Internet is exponentially distrubuted with mean equal to 4 minutes. What is the probablity that a download will require at least 2 but not more then 4 minutes. (to five decimal places)?
The pdf of the exponential distribution is:

$p(x)=\left \{ \begin{array}{cc}\frac{1}{\bar x}e^{-x/\bar x}& x \ge 0\\0&x<0 \end{array}\right$.

Here $\bar x=4$, and the required probability is:

$P(2

which you should be able to evaluate.

RonL