Grader's Comments on HW 1.


Several of you confused left skew with right skew.  The longer tail is 
the direction of the skew.

The grader does not like the expression "it is safe to say."  You can 
say something appears a certain way, and then justify it, but don't try
to gloss over the fact that nothing is certain with data.

A few of you completely ignored problem 3.

If you think something looks like a normal distribution, say why.  Do not
get carried away by small differences between the mean and median.  They usually
differ, but we only care if they differ by quite a bit.

You should not say an outlier has NO effect on the median.  Technically, it has
only a small effect.  The distinction is that I talked about moving the largest
value around - if another was moved, it could have an effect on the median.  You
should not have lost points over this, and the confusion is my fault.