Assume you conducted a cohort study to assess the relationship between cell-phone use and brain cancer. You recruit 200 individuals who use cell phones and 200 people people who do not use cell phones. After five years of follow-up, there are 10 cases of brain cancer among those who used cell phones and 5 cases of brain cancer among those who do not use cell phone. What would be the relative risk (incidence rate ratio) of brain cancer among those who use cell phones?

		2
		10
		1
		0.5