"Tail-Chasing" by Dogs Is an Anxiety Disorder Characterized by Circling

Essay

"Tail-chasing" by dogs is an anxiety disorder characterized by circling behavior withthe dog's attention directed toward its tail. There may be many reasons for tail-chasing behaviors. To investigate the potential for biochemical causes, a study wasperformed at a small animal clinic at a university. Blood samples were taken fromrandom sample of 15 dogs brought to the clinic by owners worried about the tail-chasing behaviors of their dogs. A control group consisting of a random sample of 15dogs brought to the clinic for other reasons contributed blood samples with theowner's permission. The mean lipoprotein density for the tail-chasing group was 12mg/dl, and the standard deviation was 2.24 mg/dl. The corresponding statistics forthe control group were 13 mg/dl and 1.73 mg/dl. There was no indication ofskewness in either sample distribution.a) Is there sufficient evidence to conclude that there is a difference in meanlipoprotein density in these two samples?
Provide statistical justification for yourresponse.b) Irrespective of your response in part (a), consider the design of this study. Woulda statistically significant difference in mean lipoprotein density be sufficient tomake a case that lipoprotein density is the cause of tail-chasing behavior in dogs?
Why or why not?