In: Statistics and Probability
A manufacturer of breakfast cereal is to release a new cereal
called Smores. Before Smores is to be distributed in grocery stores
across the country, the manufacturer conducts a study to determine
if (i) the height of the shelf in which the cereal is to be
displayed and (ii) the type of display will effect sales of the
cereal.
A statistician was hired to design an experiment to investigate if
- and if so, how - does the (i) shelf-height on which the cereal is
to be displayed and (ii) how Smores will be advertised in-store
influence sales. She randomly picked eighteen grocery stores in a
certain geographical region, each store having a similar sized
customer base. Two different `in-store' promotions were to be
randomly assigned to eighteen stores.
For nine stores where Promotion A was used, three stores were asked
to display Smores on the lower shelf, three on the middle shelf,
and three on the upper shelf. The same was done for the nine stores
where in store Promotion B was used. After a period of one week,
the number of boxes of Smores sold at each of the 18 stores was
recorded from the item-scanning system.
Use α=0.05 for any statistical tests.
InStorePromtion | ShelfHeight | Sales | |
1 | A | Bottom | 47 |
2 | A | Bottom | 43 |
3 | A | Bottom | 44 |
4 | A | Middle | 64 |
5 | A | Middle | 65 |
6 | A | Middle | 68 |
7 | A | Top | 41 |
8 | A | Top | 43 |
9 | A | Top | 39 |
10 | B | Bottom | 46 |
11 | B | Bottom | 40 |
12 | B | Bottom | 42 |
13 | B | Middle | 67 |
14 | B | Middle | 71 |
15 | B | Middle | 70 |
16 | B | Top | 42 |
17 | B | Top | 43 |
18 | B | Top | 46 |
Complete the partial ANOVA table below, using two decimals in
each field.
Source | Degrees of Freedom | Sum of Squares |
Promotion Type | ||
Shelf Height | ||
Interaction | ||
Error | ||
Total |
(b) You wish to test the hypothesis that the shelf-height will
effect the sales of Smores. Of the options below, select the
statistical hypothesis that will test this.
A.
H0:μBottom=μMiddle=μTopHA:μBottom≠μMiddle≠μTopH0:μBottom=μMiddle=μTopHA:μBottom≠μMiddle≠μTop
B.
H0:μBottom=μMiddle=μTopHA:atleastoneμiH0:μBottom=μMiddle=μTopHA:atleastoneμi
isdifferentisdifferent
C.
H0:μBottom≠μMiddle≠μTopHA:μBottom=μMiddle=μTopH0:μBottom≠μMiddle≠μTopHA:μBottom=μMiddle=μTop
D.
H0:μPromoA=μPromoBHA:μPromoA≠μPromoBH0:μPromoA=μPromoBHA:μPromoA≠μPromoB
(c, i) Consider your statistical hypothesis in part (b). Compute
the test statistic used to test H0H0 in part (b).
Fcalc=
(c, ii) Find the PP-value, using two decimals in your answer.
P-value=
(d) You wish to test the hypothesis that the type of Promotion will
effect the sales of Smores. Of the options below, select the
statistical hypothesis that will test this.
A.
H0:μBottom=μMiddle=μTopHA:μBottom≠μMiddle≠μTopH0:μBottom=μMiddle=μTopHA:μBottom≠μMiddle≠μTop
B.
H0:μBottom=μMiddle=μTopHA:atleastoneμiH0:μBottom=μMiddle=μTopHA:atleastoneμi
isdifferentisdifferent
C.
H0:X¯¯¯¯PromoA=X¯¯¯¯PromoBHA:X¯¯¯¯PromoA≠X¯¯¯¯PromoBH0:X¯PromoA=X¯PromoBHA:X¯PromoA≠X¯PromoB
D.
H0:μBottom≠μMiddle≠μTopHA:μBottom=μMiddle=μTopH0:μBottom≠μMiddle≠μTopHA:μBottom=μMiddle=μTop
E.
H0:μPromoA=μPromoBHA:μPromoA≠μPromoBH0:μPromoA=μPromoBHA:μPromoA≠μPromoB
(e, i) Consider your statistical hypothesis in part (d). Compute
the test statistic used to test H0H0 in part (d).
Fcalc=
(e, ii) Find the PP-value, using FOUR decimals in your
answer.
P-value =
(f) Is there an interaction between where the shelf-height at which
the Smores are to be sold and the type of promotion used in the
store? Find the test statistic and the PP-value for such a
statistical test.
Fcalc=
P-value =