Skittles, Taste the rainbow or not?
Andrew Measel
Major in Mathematics & Computer Science
Christine Boncela
Major in Mechanical Engineering
Skittles logo is taste the rainbow, but is that really the case? Are each of the flavors
equally distributed per package allowing one to have equal taste of each flavor of the rainbow.
There are five colors and/or flavors in a regular bag of Skittles. Red has the taste of strawberries,
orange the taste of oranges, yellow tastes like lemon, green the taste of lime, and purple tastes
like grape. According the Skittles website (www.skittles.com), each flavor is equally distributed
into a package thereby 20% of each flavor should occur in each package. The given hypothesis
is that 20% of each bag should contain a given flavor.
An Observational study was conducted on thirty-six packs of Skittles. The number of
each flavor was recorded for each package. The total number of Skittles per package was also
calculated. Possible bias could occur from all the packages coming from the same batch of
packaged Skittles. If the machine was not accurate or precise on the particular day the Skittles
were packaged, then the analysis calculated below is completely biased and has little to no
validity. A larger sample size in the thousands would better alleviate the possibility of such a
bias.
Looking at Table 1, one can see that none of the packages perfectly follows the supposed
distribution of equal flavor per package. Each flavor should have an equal distribution of 20%.
The data was then placed into SPSS for further analysis. Table 2 displays the results of two
normal tests against each flavor. Relative to the 36 bags of Skittles, each flavor is normally
distributed along with the total number per bag since each statistic is above .05, the test value for
normality in the study. While no one package had an exact distribution of 20% per flavor, each
flavor is normally distributed among the 36 packages examined. In addition, the total Skittles
per bag is normally distributed. Averages for each flavor can be found in Table 3. Again, more
precise and exact results can be gathered from a larger sample size.
It is notable that each flavor is normally distributed per bag although no one bag perfectly
matches the standard 20% distribution per flavor. A normal distribution over all data collected is
expected and means there is a normal distribution even though not one bag in particular carries
the 20% standard per flavor. Therefore, one can truly taste the rainbow when they open a bag of
Skittles!
Distribution Percentages per Package
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
Strawberry
16%
11%
23%
29%
21%
13%
18%
20%
18%
11%
13%
20%
18%
29%
30%
29%
11%
27%
25%
16%
16%
25%
23%
21%
21%
21%
27%
23%
25%
27%
29%
23%
14%
23%
20%
18%
Orange
16%
20%
21%
16%
29%
25%
27%
9%
9%
13%
32%
9%
16%
18%
18%
14%
32%
14%
25%
38%
20%
16%
21%
16%
14%
11%
20%
16%
25%
18%
13%
21%
23%
20%
25%
21%
Lemon
29%
29%
18%
23%
25%
32%
21%
25%
25%
32%
16%
25%
29%
25%
14%
25%
21%
20%
18%
20%
16%
30%
29%
14%
20%
25%
23%
27%
18%
25%
23%
18%
25%
14%
21%
21%
Table 1
Grape
29%
29%
20%
23%
14%
27%
13%
18%
20%
21%
20%
23%
21%
9%
30%
25%
21%
25%
21%
14%
34%
13%
16%
25%
21%
23%
14%
20%
13%
16%
25%
25%
23%
25%
18%
29%
Lime
11%
16%
23%
16%
18%
13%
25%
29%
34%
27%
25%
25%
20%
23%
13%
13%
16%
20%
16%
20%
18%
20%
13%
27%
25%
21%
21%
16%
23%
18%
20%
14%
23%
27%
21%
16%
Tests of Normality
Kolmogorov-Smirnov
Strawberry
Orange
Lemon
Grape
Lime
Package
Shapiro-Wilk
.105
.108
.142
.101
.107
.163
.948
.957
.952
.978
.968
.924
Table 2
Averages of Flavors per Bag
Strawberry
11.69
Orange
10.89
Lemon
12.78
Grape
11.86
Table 3
Lime
11.25
Total
58.47