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?
- 68%
-
28%
- 17%
- 8%
The correct answer is: B
Explanation
\(\begin{array}{c|c} \text{class-marks(x)} & \text{(freq. (f)} & \text{cum. freq.}\\\hline 9 & &3.....3\\14 & & 6....3 + 6 = 9\\ 19 & & 9.....9 + 9 = 18\\ 24 & & 3.....18 + 3 = 21\\ 29 & & 2.....21 + 2 = 23\\ 34 & & 2.....23 + 2 = 25\\ & & 25\end{array}\)
% of students scoring more than 20 marks
= \(\frac{7}{25}\) x 100% = 28%