Question

M14. #18: Wild irises are beautiful flowers found throughout the United States, Canada, and northern Europe. This problem concerns the length of the sepal (leaf-like part covering the flower) of different species of wild iris. Data are based on information taken from an article by R. A. Fisher in Annals of Eugenics (Vol. 7, part 2, pp. 179 -188). Measurements of sepal length in centimeters from random samples of Iris setosa (I), Iris versicolor (II), and Iris virginica (III) are as follows below.

I	II	III
5.8	5.6	6.7
4.1	6.8	5.3
5.4	6.8	4.3
5.4	4.8	7.7
4.5	5.1	5.9
5.5	6.9	6.8
5.1	5.2
	6.1

A)  Find SS_TOT, SS_BET, and SS_W and check that SS_TOT = SS_BET + SS_W. (Use 3 decimal places.)

B) Find d.f._BET, d.f._W, MS_BET, and MS_W. (Use 4 decimal places for MS_BET, and MS_W.)

C) Find the value of the sample F statistic. (Use 2 decimal places.)

Answer 1

Applying one way ANOVA on above data:

Source of Variation	SS	df	MS	F
Between Groups	3.804	2	1.902	2.344
Within Groups	14.606	18	0.811
Total	18.410	20

a)

SSTOT =18.410

SS_BET =3.804

SS_W 14.606

b)

d.f._BET =2

d.f._W =18

MS_BET =1.902

MS_W =0.811

c)

value of the sample F statistic =2.34