Textbook Problem

The article “Orchard Floor Management Utilizing Soil-Applied Coal Dust for Frost Protection” (Agri. and Forest Meteorology, 1988: 71–82) reports the following values for soil heat flux of eight plots covered with coal dust.

The mean soil heat flux for plots covered only with grass is 29.0. Assuming that the heat-flux distribution is approximately normal, does the data suggest that the coal dust is effective in increasing the mean heat flux over that for grass? Test the appropriate hypotheses using α = .05.