Stats: Students enter a library on the average of 2 every 3 minutes. The waiting time until the first student arrives can be modeled by an exponential random variable. How do I calculate the probability that it less than 3 mins for the first student to arrive?

Question

anonymous · Answer

if i am not mistaken you use $\lambda e^{-\lambda}$ for this one.  does that ring a bell?

anonymous · Answer

and in this case you can use $\lambda = 2$ since your time interval is 3 minutes.  
$$P(x<3)=\int_0^12e^{-2x}$$ may do it, i hope i am not steering you wrong.  lets compute and see if it looks good

anonymous · Answer

i get .865 rounded, which seems reasonable

anonymous · Answer

does this look familiar?  i could easily be wrong