00:01
Once again, welcome to a new problem.
00:05
This time we're dealing with inferential statistics.
00:11
And when it comes to inferential statistics, we have hypothesis testing.
00:18
We have hypothesis testing.
00:20
And of course, we also have confidence intervals.
00:27
So we have hypothesis testing and we have confidence intervals.
00:32
We have confidence intervals for means and we have confidence intervals for proportions and for means we could have confidence intervals for difference of means confidence intervals of difference of means now where we take the average mean values and get the errors before before determining the differences.
01:07
So we could say we could have x bar 1 minus x bar 2.
01:17
That's the main difference.
01:22
So main difference x by 1 x 2 plus minus the standard error which is t r4 over 2.
01:31
Remember t r 4 over 2 has to do with the t distribution where each side we have a critical t value.
01:41
So this side is alpha over two and this side is also alpha over two.
01:47
This is plus t alpha over two and this is minus t alpha over two.
01:53
And then we have this standard error of the differences in the means.
02:01
And so this standard error of a radical and of course we could always define the mean difference in terms of x by 1 and x by 2.
02:12
These are the sample mean differences.
02:19
So these are the sample mean differences that we're looking for in the particular problem.
02:27
So in this case, we do have a new problem.
02:33
We do have a new problem and it's based on an article.
02:39
And these are methods, methods for predicting, methods for predicting sheer strength.
02:52
So we have methods of prediction, sheer strength.
02:57
And we're dealing with steel plate garters.
03:02
We're dealing with steel plate garters.
03:05
And this is the data from two of the methods.
03:13
And so the methods are carl sruhe and lehi.
03:22
Those are the two methods.
03:25
And these are applied to nine garters.
03:32
So we have the different types of guards right here.
03:40
And then of course we have the first method.
03:45
And then we have the second method, the lehi method...