The objective of a study by Horesh et al. was to explore the hypothesis that some forms of suicidal behavior among adolescents are related to anger and impulsivity. The sample consisted of 65 adolescents admitted to a university-affiliated adolescent psychiatric unit. The researchers used the Impulsiveness-Control Scale (ICS, A-28) where higher numbers indicate higher degrees of impulsiveness and scores can range from 0 to 45. The 33 subjects classified as suicidal had an
ICS score standard deviation of 8.4 while the 32 nonsuicidal subjects had a standard deviation of 6.0. Assume that these two groups constitute independent simple random samples from two populations of similar subjects. Assume also that the ICS scores in these two populations are normally distributed. Find the 99 percent confidence interval for the ratio of the two population variances of scores on the ICS.