00:01
We have been given a confidence interval.
00:02
The interval is 6 .6 to 7 .2 pounds.
00:07
We're told it is based on a sample with sample size 20.
00:11
We want to find the sample mean and the sample standard deviation.
00:15
So we have the confidence interval in one particular form.
00:18
Another way of writing this is a point estimate, which is kind of our best guess for the parameter based on what we know, plus and minus a margin of error.
00:33
The point estimate for a population mean is the sample mean, x -bar.
00:39
So that's the midpoint of this interval.
00:44
So if i add these up and divide by 2, i get the midpoint, 6 .9.
00:53
Of the margin of error, well, it's whatever i add on to 6 .9 to get 7 .2, or subtract to get 6 .6.
01:01
So if you took this away from 7 .2, you'd get the error.
01:05
The error is 0 .3, half of the width of the interval...