In: Statistics and Probability
Another type of painted ceramic vessel is called three-circle red-on-white ( Mimbres Mogollon Archaeology). At four different sites in the Wind Mountain archaeological region, the number of such sherds was counted in local dwelling excavations.
Site I | Site II | Site III | Site IV |
14 | 14 | 39 | 11 |
28 | 8 | 17 | 20 |
5 | 37 | 10 | 15 |
22 | 2 | 49 | 37 |
12 | 25 | 16 | |
17 | 10 |
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 10% level of significance.
(a) What is the level of significance?
State the null and alternate hypotheses.
Ho: ?1 = ?2 = ?3 = ?4; H1: Exactly two means are equal.Ho: ?1 = ?2 = ?3 = ?4; H1: Exactly three means are equal. Ho: ?1 = ?2 = ?3 = ?4; H1: All four means are different.Ho: ?1 = ?2 = ?3 = ?4; 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. (Use 4
decimal places.)
(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 ? = 0.1, we do not reject H0.Since the P value is less than or equal to the level of significance at ? = 0.1, we reject H0. Since the P value is greater than the level of significance at ? = 0.1, we reject H0.Since the P value is less than or equal to the level of significance at ? = 0.1, we do not reject H0.
(e) Interpret your conclusion in the context of the
application.
At the 10% level of significance there is insufficient evidence to conclude that the means are not all equal.At the 10% level of significance there is sufficient evidence to conclude that the means are all equal. At the 10% level of significance there is insufficient evidence to conclude that the means are all equal.At the 10% 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--- Do not reject H0. Reject H0. | |||||
Within groups | ||||||
Total |
a)
level of significance=0.1
Ho: ?1 = ?2 = ?3 = ?4; H1: Not all the means are equal.
b)
SSTOT =2534.755
SSBET =430.372
SSW =2104.383
dfBET =3
dfW=17
MSBET =143.457
MSW =123.787
value of the sample F statistic =MSBET/MSW =1.159
numerator df =3
denominator df =17
c)
p vlaue =0.3543
d)
Since the P value is greater than the level of significance at ? = 0.1, we do not reject H0
e)At the 10% level of significance there is insufficient evidence to conclude that the means are not all equal
f)
Source of variation | SS | df | MS | F | p vlaue | |
treatments | 430.372 | 3.00 | 143.457 | 1.159 | 0.3543 | |
error | 2104.383 | 17.00 | 123.787 | |||
total | 2534.755 | 20.00 |
do not reject Ho