6. The article “Origin of Precambrian Iron Formations” (Econ.

Geology, 1964: 1025–1057) reports the following data on total Fe for four types of iron formation (1
carbonate, 2
silicate, 3
magnetite, 4
hematite).

1: 20.5 28.1 27.8 27.0 28.0 25.2 25.3 27.1 20.5 31.3 2: 26.3 24.0 26.2 20.2 23.7 34.0 17.1 26.8 23.7 24.9 3: 29.5 34.0 27.5 29.4 27.9 26.2 29.9 29.5 30.0 35.6 4: 36.5 44.2 34.1 30.3 31.4 33.1 34.1 32.9 36.3 25.5 Carry out an analysis of variance F test at significance level .01, and summarize the results in an ANOVA table.