00:01
So for this problem, what i'll do is first just go over the sort of approach that we'll use, and then i'll show the actual calculations using a ti84, sort of automating it to a degree.
00:11
So we have our null hypothesis is that p is greater than or equal to 0 .51, and our alternate hypothesis is that p is less than 0 .51.
00:21
The way that we would go about calculating this is we would find the test statistic, zd not, which is equal to the sample proportion p hat minus it would be our population or our hypothesized population proportion 0 .51 then we divide that by the square root of 0 .51 times 1 minus 0 .51 divided by the sample size n where it looks like for each one of these we're getting an x and an n value so it would be x over n minus 0 .51 etc.
00:59
So, that being said, we then would have that the p value, or actually i'll say it this way, we would reject the null hypothesis if the p value we calculate, which is equal to the probability of a z score being less than our standardized test statistic, z -not, is less than our alpha value.
01:31
So, in that case, let's see here.
01:34
I'll go stat, tests, z test, stats.
01:42
The mu not value that i'm putting in is 0 .51.
01:45
The standard deviation, or sigma, is going to be calculated by taking the square root of 0 .51 times 0 .49, divided by for the first case, we have n equals 112, so divided by 112.
02:07
X bar is going to be 47 over 112, and n is equal to 112.
02:17
We're testing alternate hypothesis, mu, less than mu not.
02:21
So for part a, we find that the probability is equal to, oh, pardon me, silly mistake.
02:30
I should have been using the prop z test here.
02:32
So actually, p .0 .0 .01.
02:35
X for the first one is 47, n is 112.
02:43
Calculate that.
02:44
We find our p values equal to 0 .028 roughly.
02:48
So we reject at alpha equals 0 .05.
02:55
We fail to reject at alpha equals 0 .01.
03:02
And so what we'll be doing is sort of tabulating the results for each part of the problem in the table that i have here showing the z, the p value, as well as our conclusions at the different values.
03:13
So we'll go through and do our one proportion test again.
03:20
So we have still p -not is 0 .51 for part b.
03:24
Now we have for part b, x is 124.
03:29
N is 326...