I'm taking a course in computer simulation. I have a few questions on exponential distribution. I've tried to google on the subject but could not find a satisfactory answers to my questions. Here are my questions:
1. What is the different between negative and positive exponential distribution? Quite often I've read passages in the papers: "the job arrival rate is negative exponential distribution with mean 50 seconds".
Why is it refer to negative? what would happen if we have positive exponential distribution instead?
Also, as far as I know there is only one parameter in exponential distribution which is the lamda: x.exponential( lambda). If I want to simulate this exponential distribution with mean X seconds e.g. 50 seconds, what value should i plug for lambda?
I have tried to plug lambda as 50 in the simulation but the mean value of the total generated numbers do not tally to 50.
You explanations would be very much appreciated.
Thank you.
regards,
Amril
Answer amril -
the terms "exponential distribution" and "negative exponential distribution" mean the same thing. some books use the first expression and other books, the second one.
the expression you write for the (negative) exponential distribution is incorrect.
if you rewrite it, i may be able to help you further.
i'll just mention that, depending on how the density function is written, the mean of the distribution is either lambda or 1/lambda. you should check your text to see which convention they are using.
