A survey of randomly selected university students found that 91 of the 102 rst-veer students and 95 of the 133 second-year students surveyed had purchased used textbooks in the past year. {a} Construct a 90% condence interval for the difference in the proportions of rst-year and second-year university students who purchased used textbooks. (Round your mowers to 4 decimal places. it needed.) Answer: 40.0960 . 0.2593 |) {b} If a 05% condence interval for the difference in proportion of rst-year end second-year university students who purchased used textbooks is (0.0803. 0.2754). Give an interpretation of this condence interval. We know that 95% ot the rst-year students bought between 8.03% and 27.54% higher than the proportion of second-year students who bought used textbooks. We are 95% oontident that. at this university. the proportion of rst-year students who bought used textbooks is between 8.03% and 27.54% higher than the proportion of second-year students who bought used textbooks. We are 95% condent that. at this university. the proportion of second-year students who bought used textbooks is between 8.03% and 27.54% higher than the proportion of rst-year students who bought used textbooks. We are 95% oontident that the first-year students at this university bought between 8.03% and 27.54% more used textbooks than second-year students. We know that 95% of all random samples done on the population will show that the proportion of rst-year students who bought used textbooks is between 8.03% and 27.54% higher then the proportion of seoond-yeer students who bought used textbooks. Your last answer was interpreted as follows: 0.096