4. Suppose that at a blood drive a total of n = 300 participants donate blood, and the blood type for each donor is recorded. A "universal" donor is one who has a blood type of O negative. Though their goal was to have at least 30 universal donors during the drive, a total of just 25 people donated O negative blood.
- What is the point estimate for the population proportion of universal donors, based on those who actually donated O negative blood? Recall that a point estimate for the population proportion is the sample proportion (p-hat).
b. According to the American Red Cross, the true proportion of universal donors in the U.S. population is .07.
- Using this, calculate standard error of the sample proportion, .01473
ii. Verify that normal approximation methods would be appropriate for estimating the distribution of the sample proportion (state the assumptions and check if they hold).
iii. Find and interpret. (Hint: the steps are similar to those we took in question 1 part (d).)
iv. Given that there were 300 participants in the blood drive, is it surprising that they didn't meet their goal of at least 30 universal donors? Why or why not?