1. Mo, an AP Stats student, is curious to know if there is a difference in the proportion of male and female students

who own an iPhone. He takes an SRS of 90 females and 120 male students. The survey found that 61 females and

97 males owned an iPhone.

(a) Construct and interpret a 99% confidence interval for the difference in the proportion of female and male

students who own an iPhone at Olympia High School.

(b) Does the interval give convincing evidence that there is a difference in the proportion of females and males who

own an iPhone? Explain.

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2. Principal Swenson believes Pre-Calculus Teacher A is more effective than Pre-Calculus Teacher B. An incoming

class of 200 Pre-Calculus students are randomly assigned to two groups each size 100. One group is taught by

Teacher A and one group is taught by Teacher B. At the end of the course, 60 of Teacher A's students and 44 of

Teacher B's students pass the state exam.

(a) Construct and interpret a 95% confidence interval for the difference in the proportion of students from Teacher A

and Teacher B who pass the state exam.

(b) Does the interval give convincing evidence that there is a difference in the proportion of students from Teacher A

and Teacher B who pass the state exam? Explain.