00:01
In this exercise, we refer back to exercise 9, which was the scenario of the basketball player who makes 80 % of his foul shots.
00:10
Here for part a, we are asked, what's the expected number of shots until he misses? so as discussed in exercise 9, we can consider each shot as a bernoulli trial with success or failure.
00:24
For part a, if we define success as missing the shot, so p equals 0 .2, and we define the random variable x as the number of shots that need to be taken until he misses, then x is a geometric random variable with probability of success of 0 .2.
00:54
And so the expected number of shots until a success then is the expectation for x, which for a geometric random variable is 1 over p.
01:07
In this case, that's 1 over 0 .2 or 5.
01:21
And for part b, we're asked if the player shoots 10 foul shots, how many shots do we expect them to make? so here we have 10 trials, and let's define the random variable x as the number of successes in 10 trials.
01:41
So in this case, p is equal to 0 .8 .x is the number of successes in 10 trials...