00:01
Okay, here we have another discrete random variable, and x, and it can take on the following values, minus 1 with a probability of 0 .12, 0 with a probability of 0 .19, 1 with a probability of 0 .19, 2 with a probability of 0 .26, 3 with a probability of 0 .24.
00:30
Four and we're asked about cumulative probabilities so we want to construct the cumulative distribution function which is again just the probability that x a random variable is less than or equal to the value of the cumulative function which means we just add up probabilities from left to right basically.
01:04
So the cumulative probability at minus 1 is just the probability at minus 1 because there's nothing to the left of it, and then we just start adding probabilities.
01:16
So the cumulative at 0 is 0 .19 plus 0 .12, then we add another 0 .19, and then we add 0 .26, and then finally the probability that x is less than or equal to 3 is 1 and that's the way it should be.
01:36
The cumulative should always max out at 1 and yeah that's 0 .24 times plus 0 .76.
01:44
So we can answer the questions now.
01:50
We're asked what f of 0 is f of minus i think think this says f of 2 minus f of minus 1 sometimes these questions are garbled so if i didn't if that didn't come through right just just use the logic that i'm employing and put in the right terms.
02:24
I think it's what it says...