Find the mean deviation about the mean for the data in Exercise 9 to 10
Height in cm 95−105 105−115 115−125 125−135 135−145 145−155 Number of boys 9 13 26 30 12 10
Find the mean deviation about the mean for the data in Exercise 9 to 10
Height in cm 95−105 105−115 115−125 125−135 135−145 145−155 Number of boys 9 13 26 30 12 10
Height inMid values cms xi fi fixi |xi−125.3| fi|xi−125.3| 95−105 100 9 900 25.3 227.7105−115 110 13 1430 15.3 198.9115−125 120 26 3120 5.3 137.8 125−135 130 30 3900 4.7 141135−145 140 12 1680 14.7 176.4145−155 150 10 1550 24.7 247 100 12530 1128.8
Mean(¯¯¯x)=1N∑fixi=1100×12530=125.3
Mean deviation about mean = 1N∑ni=1fi|xi−¯¯¯x|=1100×1128.8=11.28
Height inMid values cms xi fi fixi |xi−125.3| fi|xi−125.3| 95−105 100 9 900 25.3 227.7105−115 110 13 1430 15.3 198.9115−125 120 26 3120 5.3 137.8 125−135 130 30 3900 4.7 141135−145 140 12 1680 14.7 176.4145−155 150 10 1550 24.7 247 100 12530 1128.8
Mean(¯¯¯x)=1N∑fixi=1100×12530=125.3
Mean deviation about mean = 1N∑ni=1fi|xi−¯¯¯x|=1100×1128.8=11.28
