Question

Select all the groups that are significantly different from each other

Select one or more

a. 0 ft and 10 ft

b. 0 ft and 30 ft

c. 0 ft and 40 ft

d. 10 ft and 30 ft

e. 10 ft and 40 ft

f. 30 ft and 40 ft

0ft	10ft	30ft	40ft
0.045	0.045	0.044	0.098
0.043	0.031	0.044	0.074
0.04	0.043	0.048	0.154
					The dataset contains measurements of iron levels at several depths in a bay. Develop your hypotheses and at .05 significance level conduct the appropriate statistical test to determine if iron levels are different at different depths. If they are, at .05 significance level, conduct follow up tests to determine which groups are different from each other. Build the ANOVA table.

Answer 1

I had done this using MINITAB as follows-

Stat - ANOVA - One Way ANOVA - It display as follows-

From above P-value (0.010) < l.o.s(0.05) . Thus, reject Ho. We conclude that at least one mean is significantly different.

To check this ,I had done Tukey test as follows-

From above table treatment 40 ft is significantly different.It can be seen from following plot-

To check which pair of means are significantly different see the following plot-

From above plot , treatment 40 - 0, 40-10 and 40-30 are significantly different.

Thus , Correct answer is c,e and f.