Answer:
E(x), σx
Step-by-step explanation:
We have to x be their average annual income we need to find p ( x => 50000)
To find this probability we need E(x), σx
For we find p ( x => 50000) we find the z value for 50000, ie the # of standart deviations that 50000 is away form E(x)
z = (x - E(x)/σx)
now p ( x => 50000) = p (z => (x - E(x)/σx )
hence we can say that, to find p ( x => 50000) we need the parameters E(x), σx
