00:01
So you're dealing with the mean number of accidents being 2 .2 and the standard deviation being 1 .4.
00:08
And this is over a time frame for per week.
00:13
This is weekly.
00:16
And they said it definitely isn't normal because these are basically it's a non -normal distribution.
00:22
However, on this question, i think this is question 5.
00:25
If we have a sample size of 52 and find an x bar, we want to know what's true about that sampling distribution of x bar.
00:38
Well, that distribution will have a mean that will center around 2 .2, and the standard deviation of your x bar, because of the central limit theorem, will be approximately 1 .4 divided by the square root of 52, and 1 .4 divided by the square root of 52, comes out to be, about .194 and i'm just going to hit store that as a value and it will be approximately normal.
01:10
So now we will be able to answer question b and i believe that that is supposed to be an x bar.
01:16
What's the likelihood that the mean of those 52 is less than two? and so we can convert that to a z value, two minus the 2 .2 and then divided by the standard error, which again i have stored.
01:30
And so that difference is negative 0 .2 divided by that value.
01:35
So our z value is about negative 1 .03, and the area below 1 .03 is 0 .15...