In a certain examination,there were 100 candidates of whom 21 failed,6 secured distinctions,12 were placed in the first division,43 were placed in the third division and 18 in the second division.It is known that at least 75% marks are required for distinction,40% for passing,50% for second division and 60% for first division.Organise the date and calculate median,first and the third quartiles.

Class Frequency Cf
0 - 40 21 21
40 - 50 43 64
50 - 60 18 82
60 - 75 12 94
75 - 100 6 100
Total 100  

M = N2 = 1002 = 50Median class is 40-50Median = L + N2- Cff × i= 40 + 50 - 2143×10 = 46.74First Quartile-Q1 = Size of N4th item = 1004th item = 25th itemThe class corresponsing to Q1 is 40-50Q1 = l + N4- Cff × i = 40 + 25 - 2143×10    = 40.94 Third quartile-Q3 = Size of 3(N4)th item = 3(1004)th item = 75th itemThe class corresponsing to Q3 is 50-60Q3 = l + 3(N4)- Cff × i = 50 + 75 - 6443×10    = 52.5

 

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