Having done poorly on a particular exam in a junior high school, 20 students decide to write the exam again to try and improve their mark. Results are given in the following table. Student Attempt 1 (A₁) Attempt 2 (A2) Difference (d = A₁ - A₂) n 20 20 20 0. Average 54 59 -5.0 Standard deviation 3.0 4.8 2.6 (a) Find a 98% confidence interval for the difference in mean scores between attempt 1 and attempt 2. (Round your answers to 4 decimal places, if needed.) (b) Based on this confidence interval, can we conclude there is a difference in mean scores between attempt 1 and attempt 2? Yes, since the interval contains 0. Yes, since the interval is completely below No, since the interval contains 0. O No, since the interval is completely below 0.

Having done poorly on a particular exam in a junior high school, 20 students decide to write the exam again to try and improve their mark. Results are given in the following table. Student Attempt 1 (A₁) Attempt 2 (A2) Difference (d = A₁ - A₂) n 20 20 20 0. Average 54 59 -5.0 Standard deviation 3.0 4.8 2.6 (a) Find a 98% confidence interval for the difference in mean scores between attempt 1 and attempt 2. (Round your answers to 4 decimal places, if needed.) (b) Based on this confidence interval, can we conclude there is a difference in mean scores between attempt 1 and attempt 2? Yes, since the interval contains 0. Yes, since the interval is completely below No, since the interval contains 0. O No, since the interval is completely below 0.