0580 P42 - Nov 2019 - Q2 - 15 marks
13927
The cumulative frequency diagram shows times for a group of girls to solve a maths problem.
(a(i)) Estimate the median. [1]
(a(ii)) Estimate the interquartile range. [2]
(a(iii)) Estimate the 20th percentile. [1]
(a(iv)) Estimate the number taking more than 66 seconds. [2]
| Time t (seconds) | \(0<t\le20\) | \(20<t\le40\) | \(40<t\le60\) | \(60<t\le80\) | \(80<t\le100\) |
|---|---|---|---|---|---|
| Frequency | 6 | … | … | … | 4 |
(b(i)) Complete the frequency table using the diagram. [2]
(b(ii)) Estimate the mean time. [4]
Boys solving the same problem have median 60 s, lower quartile 46 s and upper quartile 66 s.
(c(i)) What percentage of boys took 66 s or less? [1]
(c(ii)) Howard says the boys’ times vary more. Explain why he is incorrect. [2]
