Teams of 15 runners took part in a charity run last Saturday. The times taken, in minutes, to complete the course by the runners from the Falcons and the runners from the Kites are shown in the table. Falcons 38 39 42 44 46 48 50 51 52 56 58 59 64 69 76 Kites 32 40 40 45 47 48 52 54 58 59 59 60 61 63 65

Mark scheme

Marking points from the official mark scheme (Oct/Nov 2024). The mark or mark type is shown in brackets.

1. [B1] Correct stem, ignore extra values (not in reverse, not split). If a split stem-and-leaf plot is used (i.e. stem values are repeated) the remaining B marks are available.
2. [B1] Correct Falcons labelled on left, leaves in order from right to left and lined up vertically, no commas or other punctuation.
3. [B1] Correct Kites labelled on same diagram, leaves in order and lined up vertically, no commas or other punctuation. Penalise each error only once in question. E.g. commas in both sets of data.
4. [B1] Correct key, for their diagram, need both teams names and 'mins' at least once here, or in leaf headings or title. If 2 separate diagrams drawn max marks B1 if both stems correct. B1 if Falcons correct to the left of the stem. B1 if both keys correct including 'mins' and team name.
5. [B1] Accept Q2, must be identified.
6. [M1] 58 < UQ < 64 – 42 < LQ < 46. Implied if both quartile values are stated and an appropriate IQR calculated accurately.
7. [A1] WWW
8. [B1] 1575/30 is not acceptable for this mark.
9. [M1] Accept unsimplified variance formula. FT their mean. Ignore any square root leading to sd for this mark.
10. [A1] AWRT. Must be identified, e.g. sd, s, std d, σ. Condone 'short' square root signs. If M1 not awarded, SC B1 for, σ = √101.3167 or √(6079/60) oe = 10.1.