Researchers asked each child in a sample of 411 school-age children if they were more or less likely to purchase a lottery ticket at a store if lottery tickets were visible on the counter. The percentage that said that they were more likely to purchase a ticket by grade level are as follows (R&J Child Development Consultants, Quebec, 2001):
Percentage That Said Theyfrom six countries. The following data were read from a graph that appeared in the paper:
ugar Depression
6 32.7
8 46.1
Country Consumption Rate
|
Korea
|
150
|
2.3
|
|
United States
|
300
|
3.0
|
|
France
|
350
|
4.4
|
|
Germany
|
375
|
5.0
|
|
Canada
|
390
|
5.2
|
New Zealand 480 5.7
a. Compute and interpret the correlation coef?cient for this data set.
b. Is it reasonable to conclude that increasing sugar consumption leads to higher rates of depression? Explain.
c. Do you have any concerns about this study that would make you hesitant to generalize these conclu- sions to other countries?