A consumer preference study compares the effects of three different bottle designs (A, B, and C) on sales of a popular fabric softener. A completely randomized design is employed. Specifically, 15 supermarkets of equal sales potential are selected, and 5 of these supermarkets are randomly assigned to each bottle design. The number of bottles sold in 24 hours at each supermarket is recorded. The data obtained are displayed in the following table.
Bottle Design Study Data
A B C
16 33 23
18 31 27
19 37 21
17 29 28
13 34 25
The Excel output of a one-way ANOVA of the Bottle Design Study Data is shown below.
SUMMARY Groups - Count - Sum - Average - Variance
Design A - 5 - 83 - 16.6 - 5.3
Design B - 5 - 164 - 32.8 - 9.2
Design C - 5 - 124 - 24.8 - 8.2
ANOVA Source of Variation - SS - df - MS - F - P-Value - F crit
Between Groups 656.1333 - 2 - 328.0667 - 43.35683 - 3.23E-06 - 3.88529
Within Groups 90.8 - 12 - 7.566667
Total 746.9333 - 14
(a) Test the null hypothesis that μA, μB, and μC are equal by setting α = .05. Based on this test, can we conclude that bottle designs A, B, and C have different effects on mean daily sales? (Round your answer to 2 decimal places.)
F =
p-value =
_ h0: bottle design _ have an impact on sales.
(b) Consider the pairwise differences μB – μA, μC – μA , and μC – μB. Find a point estimate of and a Tukey simultaneous 95 percent confidence interval for each pairwise difference. Interpret the results in practical terms. Which bottle design maximizes mean daily sales? (Round your answers to 2 decimal places. Negative amounts should be indicated by a minus sign.)
Point estimate Confidence interval
μB –μA: , [, ]
μC –μA: , [, ]
μC –μB: , [, ]
Bottle design (Click to select)ABC maximizes sales.
(c) Find a 95 percent confidence interval for each of the treatment means μA, μB, and μC. (Round your answers to 2 decimal places. Negative amounts should be indicated by a minus sign.)
Confidence interval
μA: [, ]
μB: [, ]
μC: [, ]
(a)
One-way ANOVA: No. of bottles versus Design
Source DF
SS MS
F P
Design 2 656.13 328.07 43.36 0.000
Error 12 90.80
7.57
Total 14 746.93
F =43.36
p-value =0.00
Since p-value<0.05 we conclude that bottle designs A, B, and C have different effects on mean daily sales.
(b)
Grouping Information Using Tukey Method
Design N Mean Grouping
B 5 32.800 A
C 5
24.800 B
A 5
16.600 C
Means that do not share a letter are significantly different.
Tukey 95% Simultaneous Confidence Intervals
All Pairwise Comparisons among Levels of Design
Individual confidence level = 97.94%
Design = A subtracted from:
Design Lower Center Upper
---+---------+---------+---------+------
B 11.562 16.200
20.838
(---*----)
C 3.562 8.200
12.838
(---*----)
---+---------+---------+---------+------
-10
0
10 20
Design = B subtracted from:
Design Lower Center Upper
---+---------+---------+---------+------
C -12.638 -8.000 -3.362
(----*----)
---+---------+---------+---------+------
-10
0
10 20
(c)
A consumer preference study compares the effects of three different bottle designs (A, B, and C)...
A consumer preference study compares the effects of three different bottle designs (A, B, and C) on sales of a popular fabric softener. A completely randomized design is employed. Specifically, 15 supermarkets of equal sales potential are selected, and 5 of these supermarkets are randomly assigned to each bottle design The number of bottles sold in 24 hours at each supermarket is recorded. The data obtained are displayed in the following table. Bottle Design Study Data 19 32 31 31...
A consumer preterence study compares the effects of three different bottle designs (A, B, and C) on sales of a popular fabric sortener. A completely randomized design is employed. Specifically, 15 supermarkets of equal sales potential are selected, and 5 of these supermarkets are randomly assigned to each bottle design. The number of bottles sold in 24 hours at each supermarket is recorded. The data obtained are displayed in the tollowing table Bottle Design Study Data 15 13 18 16...
A consumer preference study compares the effects of three different bottle designs (A, B, and C) on sales of a popular fabric softener. Fifteen supermarkets of equal sales potential are selected, and 5 of these supermarkets are randomly assigned to each bottle design. The number of bottles sold in 24 hours at each supermarket is recorded. The data obtained are displayed in the table. Let Pa Ho, and c represent mean daily sales using bottle designs A, B, and C,...
A consumer preference study compares the effects of three different bottle designs (A, B, and C) on sales of a popular fabric softener. A completely randomized design is employed. Specifically, 15 supermarkets of equal sales potential are selected, and 5 of these supermarkets are randomly assigned to each bottle design. The number of bottles sold in 24 hours at each supermarket is recorded. The data obtained are displayed in the following table Bottle Design Study Data 35 35 30 26...
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