00:01
Okay, so we're told that we're looking for the blood pressure for females with diabetes.
00:10
We don't know it, but we do know that the general population has a mean of 74 .4.
00:17
Sorry, 74 .4 for the regular, for the general population.
00:25
And a standard deviation of 9 .1.
00:28
And that it's normally distributed.
00:31
Okay, so that's information that's known.
00:33
We take a sample of 10 diabetic women and their mean blood pressure was 84.
00:40
Okay? we want to see if it's significantly different from the general population.
00:46
So we're going to make a two -sided 95 % confidence interval to do this.
00:54
Okay? so that's going to be x bar plus or minus z star because we know the standard deviation of the population divided by sigma over the square rate of n.
01:04
So that's 84 plus or minus 1 .96.
01:08
That's always going to be the z star for 95 % confidence.
01:12
That's how many standard deviations out from the mean you need to get to get 95 % times sigma over the square root of n, which remember n was 10 because we talked to 10 people.
01:24
Right? so 1 .96 times 9 .1 over the square root of 10 is going to give me my margin of error.
01:35
So that's 84 plus or minus 5 .64.
01:40
Okay? adding and subtracting that from 84.
01:46
So 84 minus 5 .64 is 78 .36.
01:52
And then adding, so doing 84 plus 5 .64 gives me.
01:58
89 .64.
02:00
Okay, so there is my, there is my confidence interval and i can see that the mean of the population, 74, is not in this interval, right? it's like over here.
02:14
It's not between 78 and 89.
02:16
It's outside of that, which means that it does have a significant difference.
02:20
When i do my two -sided hypothesis test, it should give me exactly the same result.
02:26
Okay, so for my hypothesis test, we have our null hypothesis...