Higher June 2022 Paper 2 Q9

9 Rosie makes phone calls to try to sell broadband.

Today, she made 120 calls.

The table shows the results.

(a) Write down the relative frequency that a call was not answered. [1 mark]

(b) During the rest of the week, Rosie will make 500 calls.

Using the results in the table, how many sales does she expect to make during the rest of the week? [2 marks]

Mark scheme (a)

Answer	Mark	Comments
\(\dfrac{33}{120}\) or \(\dfrac{11}{40}\) or 0.275 or 27.5%	B1	oe fraction, decimal or percentage

Correct answer seen with an answer of 33	B0
Ignore simplification or conversion if correct answer seen
eg1 \(\dfrac{33}{120}\) seen Answer \(\dfrac{3}{10}\)	B1
eg2 0.275 seen Answer 0.28	B1
eg3 \(\dfrac{11}{40}\) seen Answer 27.5	B1
Ignore words if correct answer seen
eg1 \(\dfrac{33}{120}\) seen Answer 11 out of 40	B1
eg2 \(\dfrac{33}{120}\), unlikely	B1
Answer given as ratio (even if correct answer also seen) eg 33 : 120	B0
Answer only in words eg 33 out of 120	B0
Only 27.5 (without %)	B0
Only 27% or 28%	B0
Only 0.27 or 0.28	B0
Only \(\dfrac{1.1}{4}\)	B0

Mark scheme (b)

Answer	Mark	Comments
\(\dfrac{6}{120} \times 500\) or [4.16, 4.17] \(\times\) 6 or [24.96, 25.02] or \(4.2 \times 6\) or 25.2 or 25 : 500 or \(\dfrac{25}{500}\)	M1	oe eg \(0.05 \times 500\) or \(500 \div 20\)
25	A1

Working and value may be seen by table
\(24 + 1\), Answer 25	M1A1
480 = 24, Answer 25	M1A1
Embedded but not selected as answer eg \(137.5 + 337.5 + 25 = 500\)	M1A0
Working for Not answered or Answered but sale not made is not choice eg ignore 137.5 and 337.5 seen
25 followed by answer 19	M1A0
If rounded or truncated values are used, the final answer must be exactly 25
eg1 \(500 \div 120 = 4.16\), \(4.16 \times 6\) Answer 25 (may have kept full value on calculator)	M1 A1
eg2 \(500 \div 120 = 4.16\), \(4.16 \times 6 = 24.96\) Answer 25 (comes from further rounding)	M1 A0