00:01
Here we consider a hypothesis test that was conducted.
00:03
There's 283 subjects, and of these 283, 17 experienced headaches.
00:12
And what we have here is the output from a calculator for the hypothesis test.
00:18
So we can see this is a 1 proportion z test, and we are testing whether a population proportion is less than 0 .12.
00:30
Now for part a, we're asked, is the test two -tailed, left -tailed, or right -tailed? so i'm going to start by answering part d.
00:41
This is usually how i determine if a test is two -tailed, right -tailed, or left -tailed.
00:45
So i first identify the hypotheses.
00:49
So one hypothesis is what we're trying to test, whether the population proportion is less than 0 .12.
00:55
And the other one would contradict this, so this would be that the proportion is 0 .12.
01:02
The null hypothesis always has to have the possibility of being equal to.
01:06
So it has to have an equal sign, less than equal sign, or greater than equal sign.
01:10
So we can see that the first option here is the null hypothesis, and therefore the second is the alternative.
01:20
We look at the alternative hypothesis to determine what type of test it is.
01:24
A less than hypothesis indicates a left -tailed test.
01:28
So the answer for a is left -tailed.
01:38
And then for b, we're asked for the test statistic...