Language. Neurological research has shown that in about 80% of people, language abilities reside in the brain's left side. Another 10% display right-brain language centers, and the remaining 10% have two-sided language control. (The latter two groups are mainly lefthanders; Science News, 161 no. 24 [2002].)
a) Assume that a freshman composition class contains 25 randomly selected people. What s the probability that no more than 15 of them have left-brain language control?
b) In a randomly assigned group of 5 of these students, what's the probability that no one has two-sided language control?
c) In the entire freshman class of 1200 students, how many would you expect to find of each type?
d) What are the mean and standard deviation of the number of these freshmen who might be right-brained in language abilities?
e) If an assumption of Normality is justified, use the 68 - 95 - 99.7 Rule to describe how many students in the freshman class might have right-brain language control.