Cancer of the colon and rectum is less common in the Mediterranean region than in other Western countries. The Mediterranean diet contains little animal fat and lots of olive oil. Italian researchers compared 1953 patients with colon or rectal cancer with a control group of 4154 patients admitted to the same hospitals for unrelated reasons. They estimated consumption of various foods from a detailed interview, then divided the patients into three groups according to their consumption of olive oil. Here are some of the data:
Olive Oil
Low Medium High Total
Colon cancer 398 397 430 1225
Rectal cancer 250 241 237 728
Controls 1368 1377 1409 4154
Data set
Use the following two-way table to analyze the data.
(Cell format: upper value = observed count, mid value = expected count, lower value = contribution to Χ2, in parentheses: column-percent).
Olive Oil
Low Medium High Total
Colon cancer 398
404.39
0.101 (32.5%) 397
404.19
0.128 (32.4%) 430
417.03
0.403 (35.1%) 1225
Rectal cancer 250
240.32
0.390 (34.3%) 241
240.20
0.003 (33.1%) 237
247.83
0.473 (32.6%) 728
Controls 1368
1371.29
0.008 (32.9%) 1377
1370.61
0.03 (33.2%) 1409
1414.14
0.019 (33.9%) 4154
Total 2016 2015 2079 6107
Is this study an experiment? Explain your answer.
A. It is not an experiment since no treatment was assigned to the subjects.
B. It is an experiment since it includes a control group
C. It is an experiment since the three groups are independent random samples
D. It is an experiment since the sample sizes are large
Χ2 = 1.5545, df = 4, P-value < 0.25.
Olive Oil
Low Medium High Total
Colon cancer 398 397 430 1225
Rectal cancer 250 241 237 728
Controls 1368 1377 1409 4154
Data set
Use the following two-way table to analyze the data.
(Cell format: upper value = observed count, mid value = expected count, lower value = contribution to Χ2, in parentheses: column-percent).
Olive Oil
Low Medium High Total
Colon cancer 398
404.39
0.101 (32.5%) 397
404.19
0.128 (32.4%) 430
417.03
0.403 (35.1%) 1225
Rectal cancer 250
240.32
0.390 (34.3%) 241
240.20
0.003 (33.1%) 237
247.83
0.473 (32.6%) 728
Controls 1368
1371.29
0.008 (32.9%) 1377
1370.61
0.03 (33.2%) 1409
1414.14
0.019 (33.9%) 4154
Total 2016 2015 2079 6107
Is this study an experiment? Explain your answer.
A. It is not an experiment since no treatment was assigned to the subjects.
B. It is an experiment since it includes a control group
C. It is an experiment since the three groups are independent random samples
D. It is an experiment since the sample sizes are large
Χ2 = 1.5545, df = 4, P-value < 0.25.
-
YES IT IS