The graph above shows the cumulative frequency curve of the distribution of marks in a class test. What percentage of the students scored more than 20 marks?
-
A.
68% -
B.
28% -
C.
17% -
D.
8%
Correct Answer: Option B
Explanation
(begin{array}{c|c} text{class-marks(x)} & text{(freq. (f)} & text{cum. freq.}\hline 9 & &3…..3\14 & & 6….3 + 6 = 9\ 19 & & 9…..9 + 9 = 18\ 24 & & 3…..18 + 3 = 21\ 29 & & 2…..21 + 2 = 23\ 34 & & 2…..23 + 2 = 25\ & & 25end{array})
% of students scoring more than 20 marks
= (frac{7}{25}) x 100% = 28%