Caffeine.
A student study of the effects of caffeine asked volunteers to take a memory test 2 hours after drinking soda. Some drank caffeine-free cola, some drank regular cola (with caffeine), and others drank a mixture of the two (getting a half-dose of caffeine). Here are the 5-number summaries for each group's scores (number of items recalled correctly) on the memory test:
|
|
n
|
Min
|
Q1
|
Median
|
Q3
|
Max
|
|
No Caffeine
|
15
|
16
|
20
|
21
|
24
|
26
|
|
Low caffeine
|
15
|
16
|
18
|
21
|
24
|
27
|
|
High caffeine
|
15
|
12
|
17
|
19
|
22
|
24
|
a) Describe the W's for these data.
b) Name the variables and classify each as categorical or quantitative.
c) Create parallel boxplots to display these results as best you can with this information.
d) Write a few sentences comparing the performances of the three groups.