00:02
Question a here, it is obvious that the random variable is discrete because the support of this variable is a set of 1, 2, 3, 4, and 5.
00:22
So it is obvious that these values are not continuous.
00:27
So the variable is discrete and b.
00:31
The probability that x equals 4 as equal to y minus the same.
00:37
Them of probability that x equals k and k belongs to the set that 1, 2, 3, and 5.
00:55
So this is equal to y minus p1, minus p 2, minus p 3, minus p 5.
01:06
And we use the values given in the table, and then we can get the probability that.
01:11
That the score is 4 is equal to 0 .19 and part c.
01:22
The probability that the score is at most 3 is equal to the probability that x smaller than or equal to 3, which because this variable is discrete, is equal to the same of p1, pt, and p3, which is equal to 0 .4 ,000, which is equal to 0 .4, 5, 2, and d, the expectation of x.
01:51
So this is equal to the same of x times p x for all possible values of x...