00:01
All right, so we are given that 10 % of people are left -handed.
00:05
So, p is going to be 0 .1.
00:07
So we have a sample of 300 people.
00:12
So we want to know what's the probability that the distribution of the proportion of left -handed.
00:18
What is the probability distribution of the proportion of left -handers in such a sample? well, in this case, that's just n times p.
00:28
So that's just 0 .1 times 30.
00:33
So we're expecting just 30 individuals to be left -handed.
00:41
And b, we want to know what is a chance that the sample proportion of left -handers would exceed 0 .12.
00:52
So we can write this as 1 minus the probability that p could be less than 0 .12.
00:59
So this is 1 minus the probability of p, z, actually.
01:06
Z being less than 0 .12 minus 0 .1 then over so our standard deviation is going to be square root of n times p times q so that's the square root of 300 times 0 .1 times 0 .9 so let's see what we get so we should expect 5 .196 so just toss that here.
01:48
196...