AuthorTopic: Skewness of Distribution??
cfaunicorn
@2010-02-02 01:55:00
I'm totally confused about the skewness of distribution. According to the text, mean=median in a normal distribution, how about the mode? And if +ve skewed,mean>median>mode. Here are my questions:
(1) Consider the sample {-12,0,3,3,4,6,6,6,12,22},where i calculated mean=5,median=5,mode=6,Sk=0.0447. The Sk formula suggests that this is +ve skewed; however, the mean=medianmedian>mode. WHY IS THAT AND HOW WILL THE GRAPH LOOK LIKE?
(2) Consider the sameple {-11,1,3,4,4,6,6,6,12,22},where i calculated mean=5.3,median=5,mode=6, Sk=0.13. This is mean>median Again, with mode being the largest, shouldn't the graph look like negatively skewed??

I'm totally confused. Can someone pls help? :(
muna
@2010-03-22 04:26:42
The key here is about the skewness of a 'normal distribution'. There are numerous characteristics about a 'normal distribution' that your samples do not satisfy. in a normal the mean or arithmetic average remains the peak, but the more common occurance (mode) will be greater than the (to the right of) the mean.
Hope this helps buddy!