00:01
You know this problem we are told that we have a binomial random variable where n is 10 and p is 0 .01.
00:11
Now we would like to find the following probabilities.
00:15
Now if we have n is 10 and p is 0 .01, this means that the probability of x is equal to 10 choose x times 0 .01 to the x times 0 .99 to the 10 minus x.
00:33
And that just comes from following our binomial distribution properties.
00:39
Now here on part a we would like to find the probability that x is five and so the probability that x is five just means plug in five for x and so this is ten choose five times point o one to the fifth times point nine nine to the fifth and evaluating this gives us the very small number of about two point three nine six times ten to the negative eighth power that is the probability that x is equal to five now on b we want the probability that x is less than or equal to two.
01:26
And so this just means we want the sum of all the probabilities from x going from zero to two of p of x, which is the sum as x goes from zero to two of ten choose x times 0 .01 to the x times 0 .99 to the 10 minus x.
01:51
And that just means we're going to take all of those values, plug 0, 1, and 2 in, and then evaluate it.
02:00
And whenever we do, we got our problem.
02:02
Probability of 0 .999...