0
$\begingroup$

I have a CDF defined as

$ 2(x+\frac{1}{x}-2) \text{ for } 1 \leq x \leq 2 $

I need to convert this into a percentile function and I'm getting a little lost in the algebra. Here's what I've done so far.

$ F(x) = 2x + \frac{2}{x} - 4 = \eta_{p} $

$ \implies 2x^2 -(4 + \eta_{p})x + 2 = 0 $

I think I'm supposed to use the quadratic formula

$ \frac{4 + \eta_p \pm \sqrt{(n_p+4)^2 - 16}}{4} = 0 $

but I don't see how this helps me.

$\endgroup$
  • $\begingroup$ you should write $x = \frac{4+n_p \pm \sqrt{(n_p+4)^2-16}}{4}$, then check the two solutions to see which it is. One will might unfeasible. $\endgroup$ – George Dewhirst Dec 3 at 0:14

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.