# Probability density function

#4. The probability density function of X, the lifetime of a certain type of electronic device (measured in hours), is given by

f (x) = 10/x2 x > 10

f (x) = 0 x ≤ 10

(a) Find P{X > 20}.

(b) What is cumulative distribution function of X?

.. (see attachment)

https://brainmass.com/statistics/probability-density-function/probability-density-function-31284

#### Solution Preview

Hello and thank you for posting your question to Brainmass!

The solution is attached below in two files. the files are identical in ...

#### Solution Summary

this shows how to find the cumulative distribution function.

$2.19