Ten percent of the world's population is left-handed. A researcher claims that left-handed individuals are more creative than those who aren't left-handed. In order to support his claim, he takes a sample of 900 artists and finds that 9% of them are left-handed. Answer the following. (If necessary, consult a list of formulas.) (a) Find the mean of p, where p is the proportion of left-handed individuals in a random sample of 900. X ? (b) Find the standard deviation of p. (c) Compute an approximation for P (p