Q2/ For the drainage system of irrigation project, 18 trocars was tested according to the difference between the water level of these trocars and the water level in the main trocar, the results were (cm): Difference in 1.0 - 2.4 2.5 - 3.9 4.0 - 5.4 5.5 - 6.9 7.0 - 8.4 water level cm FI 5 ? 3 2 2 For the previous data find the following: A Median, Mode from the frequency distribution B Standard deviation for difference in water level less than (5.5 cm). (30 Mark)