The following data refers to airborne bacteria count (number of colonies/ft3) both for...

The following data refers to airborne bacteria count (number of colonies/ft³) both for m = 8 carpeted hospital rooms and for n = 8 uncarpeted rooms (“Microbial Air Sampling in a Carpeted Hospital,” J. of Environmental Health, 1968: 405). Does there appear to be a difference in true average bacteria count between carpeted and uncarpeted rooms?

Suppose you later learned that all carpeted rooms were in a veterans’ hospital, whereas all uncarpeted rooms were in a children’s hospital. Would you be able to assess the effect of carpeting? Comment.