Blood donations from volunteers serve a crucial role in the nation's health care system. Are Americans any more or less generous about donating blood in some years than others? Are women any more or less willing to give blood than men? To investigate these questions we can analyze data from the General Social Survey, which is a national survey conducted every two years on a nationwide random sample of adult Americans.

2002 2004 Donated blood in previous 12 months 210 230 Did not donate blood in previous 12 months 1,152 1,106 Total 1.362 1,336 3. For each year, calculate the (conditional) proportion of adult Americans sampled who donated blood in the previous 12 months. Use appropriate symbols to represent them. Also calculate the difference between these sample proportions (taking the 2002 proportion minus the 2004 proportion). 2002 proportion (P 2002): 2004 proportion (P 2004): Difference in proportions (P2002 - P2004)