In: Statistics and Probability
A consumer preference study involving three different bottle designs (A, B, and C) for the jumbo size of a new liquid laundry detergent was carried out using a randomized block experimental design, with supermarkets as blocks. Specifically, four supermarkets were supplied with all three bottle designs, which were priced the same. The following table gives the number of bottles of each design sold in a 24-hour period at each supermarket. If we use these data, SST, SSB, and SSE can be calculated to be 586.1667, 421.6667, and 1.8333, respectively.
Results of a Bottle Design Experiment | ||||
Supermarket, j | ||||
Bottle Design, i | 1 | 2 | 3 | 4 |
A | 16 | 14 | 1 | 6 |
B | 33 | 30 | 19 | 23 |
C | 23 | 21 | 8 | 12 |
(a&b) Test the null hypothesis H0 that no differences exist between the effects of the bottle designs and supermarkets on mean daily sales. Set α = .05. Can we conclude that the different bottle designs have different effects on mean sales? (Round F to 2 decimal places and SS, MS to 3 decimal places. Leave no cells blank - be certain to enter "0" wherever required.)
Analysis of Variance for factorl
Tukey q.05 = 4.34, MSE = .306, s = .553, b = 4
Source | DF | SS | MS | F |
P |
Bottle | |||||
Market | |||||
Error | |||||
Total | |||||
(c) Use Tukey simultaneous 95 percent confidence intervals to make pairwise comparisons of the bottle design effects on mean daily sales. Which bottle design(s) maximize mean sales? (Round your answers 2 decimal places. Negative amounts should be indicated by a minus sign.)
AB: | [ , ] |
AC: | [ , ] |
BC: | [ , ] |
Bottle design (A, B, OR C) maximizes sales.
a & b)
using excel data analysis tool for two factor anova, following o/p Is obtained :
write data>menu>data>data analysis>anova :two factor
without replication>enter required labels>ok, and following
o/p Is obtained,
Anova: Two-Factor Without Replication | ||||||
SUMMARY | Count | Sum | Average | Variance | ||
A | 4 | 37 | 9 | 48.917 | ||
B | 4 | 105 | 26 | 40.917 | ||
C | 4 | 64 | 16 | 51.333 | ||
sample 1 | 3 | 72 | 24 | 73.000 | ||
`SAMPLE 2 | 3 | 65 | 142 | 64.333 | ||
SAMPLE 3 | 3 | 28 | 134 | 82.333 | ||
SAMPLE 4 | 3 | 41 | 13.667 | 74.333 | ||
ANOVA | ||||||
Source of Variation | SS | df | MS | F | P-value | F crit |
Rows | 586.17 | 2 | 293.08 | 959.18 | 0.00 | 5.14 |
Columns | 421.67 | 3 | 140.56 | 460.00 | 0.00 | 4.76 |
Error | 1.83 | 6 | 0.31 | |||
Total | 1009.67 | 11 |
ANOVA | |||||
Source of Variation | SS | df | MS | F-stat | p-value |
Rows | 586.167 | 2 | 293.083 | 959.18 | 0.0000 |
Columns | 421.667 | 3 | 140.556 | 460.00 | 0.0000 |
Error | 1.833 | 6 | 0.306 | ||
Total | 1009.667 | 11 |
c)
A | B | C | |
count, ni = | 4 | 4 | 4 |
mean , x̅ i =Σxi / ni | 9.250 | 26.250 | 16.000 |
Level of significance | 0.05 |
no of treatments | 3 |
df error | 6 |
MSE | 0.3056 |
q-statistic value | 4.34 |
Tukey Kramer test
critical value = q*√(MSE/2*(1/ni+1/nj))
confidence interval = mean difference ± critical value
if confidence interval contans zero, then means are not
different.
confidence interval | |||||||
population mean difference | critical value | lower limit | upper limit | result | |||
AB | -17.0 | 1.1995 | -18.20 | -15.80 | means are different | ||
AC | -6.8 | 1.1995 | -7.95 | -5.55 | means are different | ||
BC | 10.3 | 1.1995 | 9.05 | 11.45 | means are different |
Bottle design ( B ) maximizes sales.