A random sample of companies in electric utilities (I),
financial services (II), and food processing (III) gave the
following information regarding annual profit per employee (units
is thousands of dollars). Shall we reject the null hypothesis that
there is no difference in mean profit per employee at the 1% level
of significance?
I. 49.1, 43.4, 32.9, 27.8, 38.3, 36.1, 20.2
II. 55.6, 25.0, 41.3, 29.9, 39.5
III. 39.0, 37.3, 10.8, 32.5, 15.8, 42.6