Comparing Tails Vs. Comparing Means

Here is data posted at local YMCA for 30 top performers for the month of August. The images show total weights lifted by top 30 performers in men’s and women’s category.

men_weightswomen-weights

Do you think you can compare these two sets of data and go on to make generalized statement about men or women’s strengths?

Be careful here.

First this is data from only those who chose to go to YMCA to lift weights and chose to have their results recorded.

Second these are top 30 people, the right tail. You can’t compare extremes and say generalized statement about population. For that you have to compare means.

How many such measurements errors do we commit when comparing effect of marketing campaigns and sales programs?