Mathematics 9709 · AS & A Level · Sampling and estimation
Sampling and estimation — practice question
A typing test is completed by $111$ people. Their numbers of typing errors are shown in the table below, with classes $1$--$5$, $6$--$20$, $21$--$35$, $36$--$60$, $61$--$80$ and matching frequencies $24$, $9$, $21$, $15$, $42$.
(i)[5]
Draw a histogram on graph paper to show this information.
(ii)[3]
Calculate an estimated mean number of typing errors for these $111$ people.
(iii)[3]
State which class contains the lower quartile and which class contains the upper quartile. Hence find the least possible value of the interquartile range.
Worked solution & mark scheme
This 11-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Accurate finding of class widths (5, 15, 15, 25, 20)” …