S The right hand reaction times of 20 students were recorded via a data logger. Round the data, create a stem plot and comment on its shape. 0.38, 0.17, 0.492, 0.33, 0.289, 0.311, 0.33, 0.391, 0.297, 0.27, 0.234, 0.281, 0.297, 0.33, 0.266, 0.36, 0.33, 0.297, 0.301, 0.2512. ". Draw back-to-back stem plots for the following data. Give comments based on the diagram drawn. (a) 20 boys and 20 girls took part in a competition to test how long a person can hold his or her breath. Below are the timings in seconds (correct to the nearest second). Girls Boys 18 16 18 22 21 14 11 20 22 16 22 25 17 22 19 22 25 22 19 17 19 23 15 16 19 23 16 15 23 9 21 16 24 22 21 22 18 16 18 19 (b) The Mathematics and Chemistry marks for 20 students are shown in the following table. ' Mathematics 77 84 52 78 67 65 73 73 57 42 79 66 71 62 64 32 86 44 45 59 Chemistry 31 45 62 61 82 44 34 50 53 77 57 46 67 53 43 74 68 59 58 46