Which do you think produces a larger correlation between the weight and the price of diamonds: using a collection of gems of various cuts, colors, and clarities or a collection of stones that have the...

Which do you think produces a larger correlation between the weight and the price of diamonds: using a collection of gems of various cuts, colors, and clarities or a collection of stones that have the same cut, color, and clarity?

To measure the association between the number of employees and the number of items produced on a small assembly line, a company recorded the number of employees each day (from 5 to 10) and the number of items produced. To make a nicer plot, a manager found the average number of items produced when 5 employees worked, the average number when 6 worked, and so forth. He then plotted these average levels of production versus the number of employees. How does this averaging affect the correlation?