00:01
In this table we have the probability distribution for a discrete random variable x.
00:06
And for part a, we're asked if this is a valid probability distribution.
00:13
Two criteria that need to be satisfied in order to be a valid probability distribution are the first is that the summation of all of the probability masses must add to one.
00:33
And so if we add up these probabilities, they do indeed add to one.
00:37
And the second is that all of the probability masses must be between 1 and 0 inclusive.
00:52
And looking at the probability masses in the table, this is also satisfied.
00:58
So we can say that yes, this is a valid probability distribution.
01:05
And then we're asked for the probability that the variable is less than 36.
01:10
So we can write this as the probability of x being smaller than 36.
01:17
To answer this, we can go to the table, look to see what values of x...