In: Statistics and Probability
. Observation data for the three L1, L2 and L3 locations are presented in the table as below
L1 |
L2 |
L3 |
5 3 6 7 2 |
8 7 5 6 |
13 11 9 10 |
using α = 5%, test whether the conditions at the three locations are the same?
L1 | L2 | L3 | Total | |
Sum | 23 | 26 | 43 | 92 |
Count | 5 | 4 | 4 | 13 |
Mean, Sum/n | 4.6 | 6.5 | 10.75 | |
Sum of square, Ʃ(xᵢ-x̅)² | 17.2 | 5 | 8.75 |
Null and Alternative Hypothesis:
Ho: µ1 = µ2 = µ3
H1: At least one mean is different.
Number of treatment, k = 3
Total sample Size, N = 13
df(between) = k-1 = 2
df(within) = N-k = 10
df(total) = N-1 = 12
SS(between) = (Sum1)²/n1 + (Sum2)²/n2 + (Sum3)²/n3 - (Grand Sum)²/ N = 85.97308
SS(within) = SS1 + SS2 + SS3 = 30.95
SS(total) = SS(between) + SS(within) = 116.9231
MS(between) = SS(between)/df(between) = 42.98654
MS(within) = SS(within)/df(within) = 3.095
F = MS(between)/MS(within) = 13.8890
p-value = F.DIST.RT(13.889, 2, 10) = 0.0013
Decision:
P-value < α, Reject the null hypothesis.
Conclusion:
There is not enough evidence to conclude that all the three locations are the same at 0.05 significance level.
ANOVA | |||||
Source of Variation | SS | df | MS | F | P-value |
Between Groups | 85.9731 | 2 | 42.9865 | 13.8890 | 0.0013 |
Within Groups | 30.9500 | 10 | 3.0950 | ||
Total | 116.9231 | 12 |