Stumped

[luc354]

two questions have been really annoying me. I just can't seem to find a way to figure them out.

Let F(x) be the cumulative distribution function (cdf) of a discrete random variable X which has only integer values. The following values of F(x) are known: F(1) = 0.1, F(2) = 0.19, F(3) = 0.25, F(4) = 0.4, F(5) = 0.75. Find P r[2 ≤ X ≤ 4].

thank you,

 

[Dr.Peterson]

two questions have been really annoying me. I just can't seem to find a way to figure them out.

Let F(x) be the cumulative distribution function (cdf) of a discrete random variable X which has only integer values. The following values of F(x) are known: F(1) = 0.1, F(2) = 0.19, F(3) = 0.25, F(4) = 0.4, F(5) = 0.75. Find P r[2 ≤ X ≤ 4].

Always start with definitions.

What is a CDF? (Check what your own textbook says, if you forget.) In particular what does, say, F(4) mean?

 

[Steven G]

You only posted one question (??)

Before you can figure out what Pr [2 ≤ X ≤ 4], you 1st need to know what F(x) tells you. For example what does F(3) mean?