Hello and this lecture where I go to learn how to check on normality.
Were out of the histogram I'm going to use the same data pray Deeble that contain information about
a sample of Karpel and I will check whether the variable income is normally distributed by visual faction
of the histogram.
This time I will also add the normal distribution curve to the chart to the get to Grahm that low the
graphics package DZIEDZIC Block.
And now let's compute the mean and standard deviation of income I will need that information to drop
the normal distribution curve.
I would throw the value into variable am for the meeting and asked for the standard deviation that I
would do that.
Okay.
And now that bill that is to them charge with the normal distribution curve suddenly the DZIEDZIC plot
to function here in the jump histogram function.
I will define the data.
Graeme D.M. And here is the status function.
I would represent the income on the x axis and the density of the relative frequencies on the y axis
that all had to make the histogram look better.
I will fill the bins and around and then I add this tattoo function function which will drop the normal
distribution curve.
Here I must define the function itself.
It is the norm.
Normally the function that creates a normal distribution.
It comes with the stats package and the arguments of this function will be introduced with this often
parts and they will be of course the mean and standard deviation the mean is the will to AM and the
standard deviation is equal to d the new variable.
I have just created.
And on the x axis here I would represent of course the variable in my variable of Stardate.
OK let's run this all.
I hope it works OK it works that the histogram
and we can notice from the expansion of this chart the income does not seem to follow a normal distribution.
First of all it is the right.
Q So with the value of the the values have a tendency to concentrate here on the left.
So the low values are much more frequent than the five values and furthermore this distribution the
income has a very high peak.
So it's like to Carkeek distribution.
In conclusion the variable income does not seem to be normally distribution distribute it.
Sorry which is confirmed by the Shapiro will test that we ran in the previous lecture that the old Thank-You.