00:01
Based on a recent survey, we know that 28 % of employees would lay off their bosses if they could.
00:06
We have a random sample of 10 employees.
00:09
So the probability of each of these 10 wanting to lay off their boss is 28%.
00:14
0 .28.
00:16
So we have 10 independent trials, because it's a random sample, two outcomes for each, they say yes or no.
00:23
Same probability on each person.
00:25
So we have a binomial distribution.
00:29
And i'm going to use excel for this question.
00:32
If you have a graphical calculator, it might have a binomial built into it.
00:35
You can also use other software like r.
00:38
Or you can use the appendix in your textbook if it has these parameters.
00:43
On excel, the function that i need is binom.
00:48
Dist.
00:50
And there are four arguments that you insert.
00:52
They are x, the number of successes, which here means saying yes.
00:57
N, number of trials.
00:58
P probability.
00:59
Of success, and then whether or not you're using the cumulative density function or not.
01:06
So for part a, we want the probability that x is exactly three.
01:11
So in into the function, i need to put in 3, 10, 0 .28, and false, because i do not want the cumulative probability, i just want the probability of exactly 3.
01:23
So i put that in and get 0 .2624.
01:33
Part b, oops, 2642.
01:38
Wrong way around there...