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 | 30 | 21 | ||||||
14 | 29 | 21 | ||||||
14 | 31 | 22 | ||||||
19 | 33 | 24 | ||||||
15 | 33 | 26 | ||||||
You will need to enter the data into Minitab. It is easiest to copy from here into Excel. Then copy and paste from Excel into Minitab. Besure that row 1 (the first white row in the spreadsheet) contains the first piece of data and that variable names are in the top grey row in Minitab. |
(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 answers to 2 decimal places. Leave no cells blank - be certain to enter "0" wherever required.) |
F | |
p-value | |
Do not reject or reject? H0: bottle design Does or does not ? have an impact on sales. (b) Based on Tukey's results, which bottle design maximizes mean daily sales? Bottle design A, B, or C maximizes sales.
One-way ANOVA: A, B, C
Method
Null hypothesis | All means are equal |
Alternative hypothesis | Not all means are equal |
Significance level | α = 0.05 |
Equal variances were assumed for the analysis.
Factor Information
Factor | Levels | Values |
Factor | 3 | A, B, C |
Analysis of Variance
Source | DF | Adj SS | Adj MS | F-Value | P-Value |
Factor | 2 | 609.60 | 304.800 | 74.95 | 0.000 |
Error | 12 | 48.80 | 4.067 | ||
Total | 14 | 658.40 |
Model Summary
S | R-sq | R-sq(adj) | R-sq(pred) |
2.01660 | 92.59% | 91.35% | 88.42% |
Means
Factor | N | Mean | StDev | 95% CI |
A | 5 | 15.600 | 2.074 | (13.635, 17.565) |
B | 5 | 31.200 | 1.789 | (29.235, 33.165) |
C | 5 | 22.800 | 2.168 | (20.835, 24.765) |
Pooled StDev = 2.01660
Tukey Pairwise Comparisons
Grouping Information Using the Tukey Method and 95% Confidence
Factor | N | Mean | Grouping | ||
B | 5 | 31.200 | A | ||
C | 5 | 22.800 | B | ||
A | 5 | 15.600 | C |
Means that do not share a letter are significantly different.
Get Answers For Free
Most questions answered within 1 hours.