SOLUTION: The probability distribution of a discrete random variable X is given below. Value x of X: "-2, -1, 0, 1, 2" P(X=x): "0.22, 0.11, 0.26, 0.12, 0.29" Let F(x) be the cumulativ

Algebra ->  Probability-and-statistics -> SOLUTION: The probability distribution of a discrete random variable X is given below. Value x of X: "-2, -1, 0, 1, 2" P(X=x): "0.22, 0.11, 0.26, 0.12, 0.29" Let F(x) be the cumulativ      Log On


   



Question 1190605: The probability distribution of a discrete random variable X is given below.
Value x of X: "-2, -1, 0, 1, 2"
P(X=x): "0.22, 0.11, 0.26, 0.12, 0.29"
Let F(x) be the cumulative distribution function of X. Compute the following:
a) F(x=1)=
b) F(x=1)-F(x=-1)=
c) F(x=3/5)=
Any help would be appreciated, thank you!

Answer by chitrank(4) About Me  (Show Source):
You can put this solution on YOUR website!
Cumulative distribution function(CDF) is nothing but a function that tells you, given some number x, what is the probability that the random variable X would be less than or equal to that value x.
So to calculate CDF on x, or f(x) as in the question, just find out what's the probability that the random variable X will take a value less than or equal to x.
To calculate that probability, observe that X can only take one value at any given time. Therefore, to calculate the probability that X would be less than (or equal to) some x, you would only need to sum the probabilities of X taking values than or equal to x. And this sum is extremely easy because X is discrete, and hence X only takes finitely many values (which is, according to the question, one of -2,-1,0,1,2).