STAT 200 Week 6 Homework Problems

9.1.2

Many high school students take the AP tests in different subject areas. In 2007, of the 144,796 students

who took the biology exam 84,199 of them were female. In that same year, of the 211,693 students

who took the calculus AB exam 102,598 of them were female ("AP exam scores," 2013). Estimate the

difference in the proportion of female students taking the biology exam and female students taking the

calculus AB exam using a 90% confidence level.

n1=144,796

p1=84199/144796 = 0.582

q1=1-0.582 = 0.418

n2=211,693

p2=102598/211693 = 0.485

q1=1-0.485 = 0.515

zc = 1.645

E=1.645*sqrt[{(0.582*0.418)/144796}+{90.485*0.515)/211693}]

E= 0.0028

(0.582-0.485)-0.0028<p1-p2<(0.582-0.485)+0.0028

0.0942<p1-p2<0.998