Question: Do cell phones cause cancer? This is a multibillion dollar question. There are currently dozens of lawsuits pending that claim cell phones use caused cancer. To help shed light on the issue, several scientific research projects have been undertaken. One such project was conducted by Danish researchers. This 13-year study examined 420,000 Danish cell phone users. The scientists determined the number of Danes who would be expected to contract various forms of cancer. The expected number and the actual number of cell phone users who developed each type of cancer are listed below.

Cancer Expected Number Actual Number

Brain and nervous system 143 135

Salivary glands 9 7

Leukemia 80 77

Pharynx 52 32

Esophagus 57 42

Eye 12 8

Thyroid 13 13

a) Can we infer from these data that there is a relationship between cell phone use and cancer?

b) Discuss the results, including whether the data are observational or experimental. provide several interpretations of the statistics. in particular, indicate whether you can infer that cell phone use causes cancer.