A blocked analysis of variance is conducted to see if different point of purchase displays produce different results. Four displays are being tested. Drugstores and supermarkets are serving as the...

A
blocked analysis of variance
is conducted to see if different point of purchase displays produce different results. Four displays are being tested.  Drugstores and supermarkets are serving as the blocked variables. After one month the  sales results appear below.

Treatments/Displays

                                               W               X                Y              Z

             Drugstores               42               45              35              50

Blocks

Supermarkets         50               55              45              58

1. Set up all relevant hypotheses.


2. Explain the logic for blocking in this experiment.