4MA0 Higher January 2016 Paper 3 Q5

EdexcelHigherOld spec7 marksGrouped Data

5 Kim asked 40 people how many text messages they each sent on Monday.
The table shows her results.

Number of text messages sent	Frequency
0 to 4	6
5 to 9	3
10 to 14	5
15 to 19	12
20 to 24	14

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

(b) Calculate an estimate for the mean number of text messages sent. (4)

Scheme	Marks
20 to 24 oe	B1
	(1)

Mark scheme (b)

Scheme	Marks
2×6 + 7×3 + 12×5 + 17×12 + 22×14 or 12 + 21 + 60 + 204 + 308 or 605	M2
"605" ÷ 40 or \(\dfrac{2 \times 6 + 7 \times 3 + 12 \times 5 + 17 \times 12 + 22 \times 14}{6 + 3 + 5 + 12 + 14}\)	M1
15.125	A1
	(4)

Notes

M2: freq × all correct midpoint values stated (or evaluated) with intention to add (condone any two errors in midpoints or frequencies)

If not M2 then award M1 for all products \(t \times f\) (and \(t\) is consistently within the interval, including end values) and intention to add (condone any two errors in their midpoints or frequencies)

M1: dep on at least M1

A1: accept 15 or 15.1 or 15.13 from correct working with no errors
(15 without working gains M0 A0)
NB. Accept 15.1625 (using 2.25 as mi-interval in first class)

Scheme	Marks
14 ÷ 40 × 100 oe	M1
35	A1
	(2)