
Probability Plotting
I know i am being very stupid atm, but i really can seem to get the right ans off my calc. Its just part b that i need help with please ... :)
Q5 The ranking points for n = 10 chess players were: 3.2, 3.9, 5.6, 6.5,
13.8, 4.7, 12.9, 15.3, 10.6, 6.6. The logistic distribution has cumulative distribution function
F (y) = ey
1 + ey −∞ < y < ∞.
It is thought chess ranking points follow a logistic distribution and it is
proposed to test this assumption using probability plotting.
(a) Rank the observations into numerical order such that x1 < x2 <
... < xn.
(b) Find yi such that F (yi) = i
n+1
for i = 1, ..., n.
I have the answer yi = log ( i
n + 1 − i )
I thought this was right but when i go to sub in the values i cant get the right ans. I was using i=1...10, eg where i=1, yi= 13.8.
so i would e 13.8 then rearrange to get n on its own! but its wrong
Pretty please help me, thanks

Re: Probability Plotting
hmm sorry the format seems to have messed up there. please see attached picture for the question :)
2bb6a.jpg at Free Image Hosting