Thread: percentile help with CDF

I need to understand part b.

how did they get n(p)

in other words, how did they go from
p = F(n(p)) ......to n(p)

see the attachment!

That's just the quadractic equation. Let x be the percentile

so p=F(x) or

multiply by x and create a quad equation





NOW solve for x and discard the bad solution.