Mathematics 9709 · AS & A Level · Representation of data
Representation of data — practice question
Machines $A$ and $B$ each manufacture metal rods of a particular type. The lengths, in metres, of the $19$ rods from machine $A$ and the $19$ rods from machine $B$ are shown in the back-to-back stem-and-leaf diagram below. Key: $7\;|\;22\;|\;4$ means $0.227\,\text{m}$ for machine $A$ and $0.224\,\text{m}$ for machine $B$.
(a)[3]
Find the median, and also the interquartile range, for machine $A$.
(b)[3]
The median for machine $B$ is $0.232\text{ m}$, the lower quartile is $0.224\text{ m}$ and the upper quartile is $0.243\text{ m}$; use these values to draw box-and-whisker plots for $A$ and $B$.
(c)[2]
Hence make two comparisons between the lengths of the rods made by machine $A$ and those made by machine $B$.
Worked solution & mark scheme
This 8-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Correct median value $0.238$” …