*Using the hypothesis test for two variances answer the following:
1. Based on the data reported by a study, the authors concluded that the distribution of ferritin in older adults had a smaller variance than in young adults (serum ferritin is used to diagnose iron deficiency). For a sample of 15 older male adults, the standard deviation of serum ferritin (mg / l) was s1 = 52.6; for 13 young adults, the standard deviation was s2 = 84.2.
With a level of significance of 0.05, do these data confirm the conclusion of the study?
2. Toxafen is an insecticide that has been identified as a contaminant in the Great Lakes ecosystem. To investigate the effect of exposure to toxafen in animals, groups of rats were given toxafen in their diet. One study reported weight increases (in grams) of rats given a low dose (4 ppm) and control rats whose diet did not include the insecticide. The sample standard deviation of 23 control female rats was 32 g and of 12 female rats subjected to low doses was 54 g. Do these data suggest that there is more variability in weight increases at low doses than weight increases in control rats?
Assuming normality, perform a hypothesis test with a significance level of 0.05.