Normal III

 

A Wonderful Guy

I'm as corny as Kansas in August,
I'm as normal as blueberry pie.
No more a smart little girl with no heart,
I have found me a wonderful guy!

One Blueberry Pie distribution coming right up!

In a normal distribution, the mean is equal to the median. (Or as Donald Trump Junior so famously put it “That’s how math works”).  However the mean is not always equal to the median in many distributions.  This is often only because the negative numbers are not reported because of where the y-axis is being set.  For example saying that temperatures are 40 below zero is only because the temperature is being measured on a relative scale, not on an absolute scale.  If an absolute scale had been used, then the median should be equal to the mean for a normal distribution.  Stating the median and the mean with a with a relative rather than an absolute zero, allows the calculation of the variance, if negative values had been allowed

NAR, the National Association of Realtors, has reported the mean ($639,000) and median ($396,500) prices for existing home sales.  Since the mean is not equal to the median this is hardly normal. It is suggested that this might be because negative sales prices are obviously not reported.  But if they could be reported, then if this was a normal distribution then no values would be observed for the mean minus 3 times the square root of the variance.  This requires that the variance must be the mean²/9=45.37 million.  It has already been reported that 50% of the homes sell for less than $396,500. If this were also a normal distribution, then 68% of the existing homes should sell for less than $852,000;  95% of the existing homes should sell for less than $1,065,000 and 100% of the existing homes should sell for less than  $1,278,000.  If there are existing homes selling for more than $1.3 million, then that also indicates that the existing home sales prices are not normal.