So I have a question in front of me which reads: 'If component lifetime is exponentially distributed with parameter,obtain an expression for the proportion of components whose lifetime exceeds the mean value by more than 1 standard deviation.'
I need some guidance in approaching this question, any tips on solving it would be great. Thinking it through, it seems as though I may need to use:
the standard variance formula, but before I do that I need to find the mean of the exponential distribution, and only then find the variance.
Am I on the right path ?
Any help is appreciated.