"In Exercises 9-12, find the critical value tc for the level of confidence c and sample size n. 9. C = 0.80, n = 10 11. C = 0.98, n = 15 10. C = 0.95, n = 24 12. C = 0.99, n = 30 In Exercises 13-16, (a) find the margin of error for the values of c, s, and n, and (b) construct the confidence interval for µ, using the t-distribution. Assume the population is normally distributed. 13. c = 0.90, s = 25.6, n = 16, x = 72.l 14. c = 0.95, s = 1.1, n = 25, x = 3.5 15. c = 0.98, s = 0.9, n = 12, x = 6.8 16. c = 0.99, s = 16.5, n = 20, x = 25.2 17. In a random sample of 36 top-rated roller coasters, the average height is 165 feet and the standard deviation is 67 feet. Construct a 90% confidence interval for µ,. Interpret the results. (Source: POP World Media, LLC) 18"