Dora et al. (A-31) investigated spinal canal dimensions in 30 subjects symptomatic with disc herniation selected for a discectomy and 45 asymptomatic individuals. The researchers wanted to know if spinal canal dimensions are a significant risk factor for the development of sciatica. Toward that end, they measured the spinal canal dimension between vertebrae L3 and L4 and obtained a mean of 17.8 mm in the discectomy group with a standard deviation of 3.1. In the control group, the mean was 18.5 mm with a standard deviation of 2.8 mm. Is there sufficient evidence to indicate that in relevant populations the variance for subjects symptomatic with disc herniation is larger than the variance for control subjects? Let a ¼ :05.