Question

Water samples were taken at three different locations in a river to determine whether the quantity of dissolved oxygen, a measure of water polution, varied from one location to another. The results are given in the table below.

1	2	3
5.8	6.1	3.8
6.3	6.7	3.5
5.2	6.5	3.9
5.8	6.3

If we were to use ANOVA to analyze this data, and wanted to construct a normal probability plot of the residuals, what would be the numerical values (in order) of the first two numbers that would go on the x-axis?

(a)	[2 marks] What is the value of the test statistic?

(b)	[1 mark] What is the 5% critical value?

Answer 1

ANOVA
OBSERVATION
	Sum of Squares	df	Mean Square	F	Sig.
Between Groups	12.873	2	6.437	57.587	.000
Within Groups	.894	8	.112
Total	13.767	10

A) The value of the test statistics is F=57.587 which can be obtained from the ANOVA table.

B) Critical value at 5% is 0.000 which can be obtained from the ANOVA table.