00:01
Alright, so in this case we're told that a 95 % confidence interval has been computed, and it has come out to 64 .687 approximately, up to 69 .520, about, right, approximately.
00:18
So, first thing we're supposed to say is what this means, okay? this is for a.
00:24
And basically, there's only one really right way to do this.
00:29
You're always going to start with the confidence level, so we are 95 % confident that the true mean for the population, so the mean is between these two values.
00:46
Or in other words, that this interval contains the true mean.
00:49
So this would be answer choice c.
00:52
If it has anything about, like, there's a 95 % probability that's wrong, or, like, talking about the sample mean that's wrong, needs to talk about the population mean, and that we are 95 % confident, okay? so that's c for that.
01:09
B asks, what is the margin of error? so, in a confidence interval, right, you always have the estimate plus minus the margin of error.
01:20
So the estimate is always in the middle of the confidence interval, and the margin of error would be how much you go out.
01:26
So, in other words, here's the x bar.
01:29
We go a margin of error up and a margin of error down to get the bounds of our confidence interval...