In 2005, a study was conducted to examine the effects of traumatic brain injury (TBI) on the development of Alzheimer's disease. The study population consisted of 5,000 women aged 65 years, of which 1,500women had experienced a TBI and 3,500 had never experienced a TBI. At the baseline examination, January 1, 2005, 400 cases of Alzheimer's disease were reported, 150 of which were in women with a history of TBI. All participants without Alzheimer's disease initially were available for subsequent examination over the next 10 years. From these examinations, 250 new cases of Alzheimer's disease were reported in the total group, with 75 of these reported by women with no history of TBI. (25 points; no more than 1 page; show your work)

a.Calculate the point prevalence of Alzheimer's disease in the study population as of January 1, 2015. [4]

b.Calculate the cumulative incidence (per 100 people) of Alzheimer's disease for the 10 years among females with a history of TBI. [7]

c.Calculate the cumulative incidence (per 100 people) of Alzheimer's disease for the 10 years among females with no history of TBI. [7]

d.Calculate the cumulative incidence (per 100 people) of Alzheimer's disease for the 10 years in the total population. [7]