00:01
Alright, in your question you're to use the empirical model to answer a few questions about given information from a normal distribution.
00:09
So what the empirical model shows is in a normal model, which i'm going to sketch out here, we have the mean, which in your case is 1500, and we expect 68 % of the data to fall within one standard deviation above or below the mean.
00:30
So that would be 1250 or 1750.
00:34
That's where we would expect to find 68 % of the data.
00:38
If we go out two standard deviations, we'll take another 250 off, that's 1000 to the left and 2000 to the right.
00:49
At that stage, we expect 95 % of the data to fall between those two values.
00:58
And if you go out three standard deviations, which would be 750 and 2250, we expect 99 .7 % of the data to be between those two values.
01:15
Alright, so let's take a look at your questions.
01:17
The first question is what percent lies between 1250 and 1750? we've already answered that question, it's 68%.
01:31
Okay, part b is what percent of the rents are less than 1250? so when you start getting questions like this, it's a little bit more challenging because it's not one of the answers directly on the model.
01:48
So what i first want to do is think about splitting that 68 in half.
01:52
That would leave this version right here 34%.
01:55
From center left is 50%.
01:58
So what we would do is take the 50 % and subtract the 34 % to have what's remaining in this region.
02:09
So 50 minus 34 is 16%...