answers

9. Construct confidence intervals from a mean of My = 1.25, standard error of s, = 0.45, and df = 10 at the 90%, 95%, and 99% confidence levels. Describe what happens as confidence changes and whether to reject HO. 10. A professor wants to see how much students learn over the course of a semester. A pre-test is given before the class begins to see what students know ahead of time, and the same test is given at the end of the semester to see what students know at the end. The data are below. Test for an improvement at the = .05 level. Did scores increase? How much did scores increase? Pre-test Post-test X 90 89 60 66 95 99 93 91 95 100 67 64 89 91 90 25 94 95 83 89 75 82 87 92 82 83 82 85 88 93 66 69 o = 90 100 95 96 o [ o | oo =l eh