00:01
For this question, we want to test the claim that a diet has no effect.
00:04
So that is, we want to test whether the mean weight loss is zero or not.
00:10
And we're asked to test at a significance level of 0 .01.
00:15
To do so, we have a sample of 40 people who took the diet and the mean weight loss for the sample was 6 .6 pounds with a sample standard deviation of 10 .8 pounds.
00:29
Our null hypothesis would be that the mean weight loss is nothing, so the diet is ineffective.
00:36
And the alternative is that the mean weight loss is negative, so that we actually lose weight on this diet.
00:45
So i'm doing a directional test here rather than a two -sided test or a two -tailed test.
00:50
And that's because diets are intended to have the person lose weight.
00:56
So we want to know if the diet is effective.
00:58
We want to know if, on average, we are losing weight if you go on this diet.
01:03
Since we don't have the population standard deviation, we are relying on using the sample standard deviation...