Probability question: If Pr(X=x) = x(x+1)/40 for 0 <= x &

[Guest]

If Pr(X=x) = x(x+1)/40 for 0 < x < n:

a. Find the value of n
b. Find the probability distribution for x as a table.
c. Find the expected value of X.

thank you in advance

 

[Guest]

(a) n =5

(b) Just insert values between 0 and 4 into the given function!!!

Sum of Pr(X=x) = 1

(c) E(x) = 0*0 + 1*0.05 + 2*0.15 + 3*0.3 + 4*0.5
E(x) = 3.25

 

[Guest]

Well its between 0 and 4

But if n = number of trials
n would be 5