Another type of painted ceramic vessel is called three-circle red-on-white ( Mimbres Mogollon Archaeology). At four different sites in an archaeological region, the number of such sherds was counted in local dwelling excavations.
Site I | Site II | Site III | Site IV |
18 | 11 | 37 | 17 |
28 | 4 | 19 | 23 |
9 | 35 | 11 | 17 |
22 | 3 | 45 | 36 |
10 | 29 | 19 | |
11 | 11 |
Shall we reject or not reject the claim that there is no difference in the population mean three-circle red-on-white sherd counts for the four sites? Use a 5% level of significance.
(a) What is the level of significance?
State the null and alternate hypotheses.
Ho: μ1 = μ2 = μ3 = μ4; H1: Exactly three means are equal.Ho: μ1 = μ2 = μ3 = μ4; H1: Exactly two means are equal. Ho: μ1 = μ2 = μ3 = μ4; H1: All four means are different.Ho: μ1 = μ2 = μ3 = μ4; H1: Not all the means are equal.
(b) Find SSTOT, SSBET, and
SSW and check that SSTOT =
SSBET + SSW. (Use 3 decimal places.)
SSTOT | = | |
SSBET | = | |
SSW | = |
Find d.f.BET, d.f.W,
MSBET, and MSW. (Use 3 decimal
places for MSBET, and
MSW.)
dfBET | = | |
dfW | = | |
MSBET | = | |
MSW | = |
Find the value of the sample F statistic. (Use 3 decimal
places.)
What are the degrees of freedom?
(numerator)
(denominator)
(c) Find the P-value of the sample test statistic.
P-value > 0.1000.050 < P-value < 0.100 0.025 < P-value < 0.0500.010 < P-value < 0.0250.001 < P-value < 0.010P-value < 0.001
(d) Based on your answers in parts (a) to (c), will you reject or
fail to reject the null hypothesis?
Since the P-value is greater than the level of significance at α = 0.05, we do not reject H0.Since the P-value is less than or equal to the level of significance at α = 0.05, we reject H0. Since the P-value is greater than the level of significance at α = 0.05, we reject H0.Since the P-value is less than or equal to the level of significance at α = 0.05, we do not reject H0.
(e) Interpret your conclusion in the context of the
application.
At the 5% level of significance there is insufficient evidence to conclude that the means are not all equal.At the 5% level of significance there is sufficient evidence to conclude that the means are all equal. At the 5% level of significance there is insufficient evidence to conclude that the means are all equal.At the 5% level of significance there is sufficient evidence to conclude that the means are not all equal.
(f) Make a summary table for your ANOVA test.
Source of Variation |
Sum of Squares |
Degrees of Freedom |
MS | F Ratio |
P Value | Test Decision |
Between groups | ---Select--- p-value > 0.100 0.050 < p-value < 0.100 0.025 < p-value < 0.050 0.010 < p-value < 0.025 0.001 < p-value < 0.010 p-value < 0.001 | ---Select--- Do not reject H0. Reject H0. | ||||
Within groups | ||||||
Total |
a) level of significance =.05
Ho: μ1 = μ2 = μ3 = μ4; H1: Not all the means are equal.
b) SSTOT=2665.81 SSBET=411.61, SSW=2254.20 and checked that SSTOT = SSBET + SSW
c) d.f.BET=3, d.f.W=17, MSBET=137.2 , MSW=132.6
Sample F statistic=1.035
df(numerator)=3
df(denominator)=17
c) P-value > 0.1000
d) Since the P-value is greater than the level of significance at α = 0.05, we do not reject H0
e) At the 5% level of significance there is insufficient evidence to conclude that the means are not all equal
f) ANOVA Table
Df SS MS F
p value Decision
Between 3 411.61 137.2 1.0347 p-value > 0.100 Do not
reject H0
Within 17 2254.20
132.6
Total 20 2665.81
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