The following data refers to airborne bacteria count (number of colonies/ft3) both for carpeted hospital
rooms and for 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?
Carpeted 11.8 8.2 7.1 13.0 10.8 10.1 14.6 14.0
Uncarpeted 12.1 8.3 3.8 7.2 12.0 11.1 10.1 13.7
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.