00:01
For part a, we have that n, the number of trials for this experiment, is equal to the number of people that were asked, so we have n equals 25.
00:11
Then for p, that is the probability of success, that would be equal to the proportion of all americans over the age of 5 who have gotten at least one covid vaccine, so that would be p is equal to 0 .79.
00:23
Then for part b, to find the binomial distribution, so that would be equal to n choose 15 times p to the power of 15 times 1 minus p to the power of n minus 15.
00:44
So plugging in our values, let's see here, we'd have 25 factorial divided by 15 factorial times 25 minus 15 factorial, that's that n choose 15, times 0 .79 to the power of 15 times 0 .21 to the power of 25 minus 15, which gives a result of 0 .016 when rounded to three decimal places, 0 .016.
01:10
Now for part c, to find the probability that more than 17 people say yes, probability of x greater than 17, i'll use something a little bit different here, i'll show how to do this using a ti -84, because, oh, let me get that back on screen, because we are, this is something that you can do by hand, it would just be very tedious, because you have to calculate out probability that x equals 18, 19, 20, 21, 22, 23, 24, and 25, and add them together...