Hi,
How to calculate the mean of the distribution of a random variable? Take the exponential distribution with the probability density function f(x)=lambda.exp(-lambda.x) where lambda is a constant and x is a random variable. The mean of this distribution is the reciprocal of lambda. If the mean is the expected value of x, which for a continuous random variable E(x) = Integral (x.f(x))dx, how could E(x) be the reciprocal of lambda?
Regards,
Carol
*
* For searches and help try:
* http://www.stata.com/help.cgi?search
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/
