The given table shows the Marks obtained by students in Mathematics.
MarksNo. of Students0−10310−20720−301230−401540−502050−60960−70870−801680−901490−1006
Using the table determine the Lower Quartile by drawing an ogive curve.
MarksNo. of StudentsCumulative FrequencyPoints to be plotted0−1033(10,3)10−20710(20,10)20−301222(30,22)30−401537(40,37)40−502057(50,57)50−60966(60,66)60−70874(70,74)70−801690(80,90)80−9014104(90,104)90−1006110(100,110)
The No. of observations n = 110 (Sum of frequency)
Lower Quartile = n4 = 1104 = 27.5
So the 27.5th Observation will give the Value for Upper quartile when we extend it to meet the ogive and then drop a line from it to the x-axis.
As we can see from the graph, The value obtained is 34