Question

Levi-Strauss Co manufactures clothing. The quality control department measures weekly values of different suppliers for the percentage difference of waste between the layout on the computer and the actual waste when the clothing is made (called run-up). The data is in table #11.3.3, and there are some negative values because sometimes the supplier is able to layout the pattern better than the computer ("Waste run up," 2013). Do the data show that there is a difference between some of the suppliers? Test at the 1% level.

Table #11.3.3: Run-ups for Different Plants Making Levi Strauss Clothing

Plant 1	Plant 2	Plant 3	Plant 4	Plant 5
1.2	16.4	12.1	11.5	24
10.1	-6	9.7	10.2	-3.7
-2	-11.6	7.4	3.8	8.2
1.5	-1.3	-2.1	8.3	9.2
-3	4	10.1	6.6	-9.3
-0.7	17	4.7	10.2	8
3.2	3.8	4.6	8.8	15.8
2.7	4.3	3.9	2.7	22.3
-3.2	10.4	3.6	5.1	3.1
-1.7	4.2	9.6	11.2	16.8
2.4	8.5	9.8	5.9	11.3
0.3	6.3	6.5	13	12.3
3.5	9	5.7	6.8	16.9
-0.8	7.1	5.1	14.5
19.4	4.3	3.4	5.2
2.8	19.7	-0.8	7.3
13	3	-3.9	7.1
42.7	7.6	0.9	3.4
1.4	70.2	1.5	0.7
3	8.5
2.4	6
1.3	2.9

Answer 1

lets us consider

:there is no difference between some of the suppliers

H1 : there is a difference between some of the suppliers

using minitab to test the claims

Method
Significance level α = 0.01

Equal variances were assumed for the analysis.

Factor Information

Factor Levels Values
Factor 5 plant 1, plant 2, plant 3, plant 4, plant 5

Analysis of Variance

Source DF Adj SS Adj MS F-Value P-Value
Factor 4 450.9 112.73 1.16 0.334
Error 90 8749.1 97.21
Total 94 9200.0

Model Summary

S R-sq R-sq(adj) R-sq(pred)
9.85962 4.90% 0.67% 0.00%

Means

Factor N Mean StDev 99% CI
plant 1 22 4.52 10.03 (-1.01, 10.05)
plant 2 22 8.83 15.35 ( 3.30, 14.36)
plant 3 19 4.83 4.40 (-1.12, 10.78)
plant 4 19 7.489 3.657 (1.537, 13.442)
plant 5 13 10.38 9.56 ( 3.18, 17.57)

Pooled StDev = 9.85962

the p value is 0.334

since p value is greater than 0.01 so we accept H0 and conclude that there is no difference between some of the suppliers