Foundation January 2021 Paper 1 Q18

EdexcelCurrent spec5 marksGrouped Data

18 The table gives information about the speeds, in kilometres per hour, of 80 motorbikes as each pass under a bridge.

Speed (\(s\) kilometres per hour)	Frequency
\(40 \lt s \leqslant 50\)	10
\(50 \lt s \leqslant 60\)	16
\(60 \lt s \leqslant 70\)	19
\(70 \lt s \leqslant 80\)	23
\(80 \lt s \leqslant 90\)	12

(a) Write down the modal class. (1)

(b) Work out an estimate for the mean speed of the motorbikes as they pass under the bridge.
Give your answer correct to 3 significant figures. (4)

Scheme	Marks
\(70 \lt s \leqslant 80\)	B1
	(1)

Mark scheme (b)

Scheme	Marks
10 × 45 + 16 × 55 + 19 × 65 + 23 × 75 + 12 × 85 or 450 + 880 + 1235 + 1725 + 1020 (= 5310)	M2
“5310” ÷ 80	M1
66.4	A1
	(4)
	(5 marks)

Notes

M2: \(f \times d\) for at least 4 products with correct mid-interval values and intention to add.

If not M2 then award M1

for \(d\) used consistently for at least 4 products within interval (including end points) and intention to add

or

for at least 4 correct products with correct mid-interval values with no intention to add

M1: dep on at least M1 allow division by their \(\sum f\) provided addition or total under column seen

A1: accept 66.37 – 66.4