SEMESTER II, 2010/2011 The alkalinity, in milligrams per liter, of water in the upper reaches and lower reaches of Pahang River are known to be normally distributed and the variances of the alkalinity for both reaches are assumed to be same. A sample of alkalinity readings for the upper reaches and lower reaches of Pahang River are given below. Give your answers in 2 decimal places. Upper 91 75 91 88 94 63 86 77 71 69 reaches Lower 86 95 135 121 68 64 113 108 79 62 reaches 143 108 121 85 97 Find the 98% confidence interval for the difference between two means of the alkalinity of water in the lower and upper reaches of the river and explain your answers