Question

I need to find the Odds Ratio using this data. How do you calculate it?

College	Student	Hrs of sleep	Sexual Assault victim	Sleep < 7 hours/night
1	1	5	0	1			Exposure: Did student get on average <7 hours sleep/night (1 = Yes; 0 = No)
1	2	5	0	1			Outcome: Is student a sexual assault victim (1 = Yes; 0 = No)
1	3	X	0	0
1	4	6	1	1
1	5	5	0	1				Set up 2x2 table
1	6	6	0	1					Yes, victim	No, not victim
1	7	6	0	1				<7 hours of sleep
1	8	6	0	1				>7 hours of sleep
1	9	6	0	1
1	10	6	0	1
1	11	6	1	1
1	12	6	0	1
1	13	7	0	0
1	14	7	1	0
1	15	7	0	0
1	16	7	0	0
1	17	7	0	0
1	18	7	0	0
1	19	8	1	0
1	20	8	1	0
2	21	5	1	1
2	22	5	0	1
2	23	5	0	1
2	24	5	0	1
2	25	6	0	1
2	26	6	0	1
2	27	6	0	1
2	28	6	0	1
2	29	6	0	1
2	30	6	0	1
2	31	6	0	1
2	32	6	0	1

Answer 1

	sleep<7(1)	sleep>7(0)	sexual assault victim	sleep hours
				0	1
sexual assault = 1	3	3		0	1
				0	0
sexual assault = 0	20	6		1	1
				0	1
				0	1
				0	1
				0	1
				0	1
				0	1
				1	1
				0	1
				0	0
				1	0
				0	0
				0	0
				0	0
				0	0
				1	0
				1	0
				1	1
				0	1
				0	1
				0	1
				0	1
				0	1
				0	1
				0	1
				0	1
				0	1
				0	1
				0	1/

	sleep<7(1)	sleep>7(0)
sexual assault = 1	a=3	b=3
sexual assault = 0	c=20	d=6

odds ratio = (a/c)/(b/d)

= (3/20)/(3/6)

= 0.15/0.5

= 0.3