1. A study conducted by Ariel Mutual Funds and Charles Schwab Corporation surveyed 500 African American with an annual income above $50,000 and 500 white Americans with an annual income above $50,000. The results indicated that 74% of the African Americans and 84% of the whites owned stocks (Cheryl Winokur Munk, "Stock-Ownership Race Gap Shrinks,". "The Wall Street Journal, June 13, 2002, B11). Is there a difference between the proportion of African American with an annual income above $50,000 who invest in stocks and the proportion of whites with income an annual income above $50,000 who invest in stocks at a 95% level of confidence?
2. A 10-year study conducted by the American Heart Association provided data on how age related to the risk of strokes. Suppose that the following data was obtained in a follow-up study. Risk is interpreted as the probability that the patient will have a stroke over the next 10-year, ...
[See the attached questions file.]
Neat, step-wise solutions are provided.