00:01
Hi, i'm david and i'm here to help you to answer your question.
00:04
So let me summarize your question here.
00:07
We have a binomial probability exponent and then we're given that x will be the number of the success and then we will have the end.
00:27
It will be the number of the child and it will equal to the 13.
00:33
The probability of success equal to p and equal to 0 .3.
00:42
Now they ask you know to find the probability of the x smaller equal to 4.
00:48
First, here they tell us that the x follow the binomial with the n p.
00:56
Now recall you that for the binomial, the probability x equal to k, it will equal to the n choose k, times with the p power k times with the one minus p power n minus k now here if we apply the formula first x small equal to four means that it will can happen that x can equal to zero because zero is more than four next it can be one it can be two it can be three and the last one it can also be four because we see that this one has the ecosign here.
01:36
Now it means that for each of them we apply this formula here with the n equals 13 and p equals 0 .3.
01:44
So we have here the 13 to 0 times the probability 0 .3 power 0 and 1 minus 0 .3 can be 0 .7 power 13...