For the next 3 problems, suppose a researcher takes a simple random sample of 100 high school students, and finds that the number of books read per year per student has a mean of 7.2, a median of 7.0, a 25th percentile of 2.0, and a 75th percentile of 11.0. She finds a 95% CI for the mean number of books read per year per student among high school students in general is 7.2 +/- 2.0. _____ 4. Find s, the sample standard deviation of the number of books read per year among the 100 students in the sample. a. 5.40. b. 7.23. c. 7.90. d. 8.24. e. 10.2. f. None of the above. _____ 5. What is the IQR of the number of books read per year per student? a. 7.0 b. 8.0. c. 9.0 d. 10.0 e. 11.0. f. None of the above