Question Bank › IGCSE Data, Probability & Sets › Averages (including IQR)
Averages (including IQR) Topic Basic Probability (3) Multiple Events (4) Tree Diagrams (3) Sets (4) Averages (including IQR) (5) Grouped Data (2) Cumulative Frequency (3) Histograms (3) Pie Charts (1) Time-Series (0) Frequency Polygons (0) Bar Charts & Pictograms (0) Current PowerPoint version
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Higher June 2025 Paper 1R Q13
13 Here are the numbers of eggs laid by some hens on each of 11 days in June.
9 10 12 15 17 18 19 19 20 25 26
Work out the interquartile range of the numbers of eggs.
(2)
Mark scheme
Mark scheme Scheme Marks 20 (−) 12 M1 Correct answer scores full marks (unless from obvious incorrect working) Answer: 8A1 (2) (2 marks)
Notes M1: for both values unambiguously identified
Higher June 2025 Paper 2R Q8
8 The mean of 7 numbers is 60
The mean of 3 of the numbers is 46
Work out the mean of the other 4 numbers.
(3)
Mark scheme
Mark scheme Scheme Marks 60 × 7 (= 420) or 46 × 3 (= 138) M1 “420” – “138” (= 282) M1 Correct answer scores full marks (unless from obvious incorrect working) Answer: 70.5A1 (3) (3 marks)
Notes M1: may be embedded within an equation
M1: for a method to find the sum of the 4 numbers Allow this mark if they do further incorrect work using 282
A1: allow \(\dfrac{141}{2}\) oe eg \(\dfrac{282}{4}\) or \(70\dfrac{1}{2}\)
Higher June 2025 Paper 2 Q1
1 Rio has six cards. He writes a number on each card so that
the range of the numbers is 10 the median of the numbers is 7.5 the mode of the numbers is 6
Rio arranges the cards so that the numbers are in order of size.
Three of the numbers are hidden.
Complete the cards above to show the three numbers that are hidden.
(3)
Mark scheme
Mark scheme Scheme Marks 1st card = 4 B1 2nd card = 6 B1 4th card = 9 B1 (3) (3 marks)
Notes B1: or a list of 6 numbers with a mode of 6
SCB2 for 4, 6 and 9 in the incorrect order
Higher November 2024 Paper 2 Q8
8 Kim puts 4 bananas in a bag. The mean weight of the 4 bananas in the bag is 145 grams.
Andy puts one more banana into the bag. The mean weight of the 5 bananas in the bag is 142 grams.
Work out the weight of the banana that Andy puts into the bag.
(3)
Mark scheme
Mark scheme Scheme Marks 4 × 145 (= 580) or 5 × 142 (= 710)
or
\(\dfrac{145 + 145 + 145 + 145 + x}{5} = 142\) oe
M1 5 × 142 – 4 × 145 or “710” – “580” or \(145 + 145 + 145 + 145 + x = 5 \times 142\) M1 Correct answer scores full marks (unless from obvious incorrect working) Answer: 130A1 (3) (3 marks)
Notes M1: for one correct product or for a correct equation for the weight of the last banana
M1: A fully correct method to find the weight of the 5th banana or a fully correct equation to find the missing weight with no denominator
Higher November 2024 Paper 1 Q1
1 The table shows some information about the hourly rates of pay of 60 workers.
Hourly rate of pay (\(p\) dollars) Frequency
\(10 \lt p \leqslant 15\) 18
\(15 \lt p \leqslant 20\) 16
\(20 \lt p \leqslant 25\) 14
\(25 \lt p \leqslant 30\) 8
\(30 \lt p \leqslant 35\) 4
(a) Write down the modal class. (1)
(b) Work out an estimate for the mean hourly rate of pay of the 60 workers. (4)
Mark scheme (a) Mark scheme (b)
Mark scheme (a) Scheme Marks \(10 \lt p \leqslant 15\) B1 (1)
Notes B1: allow \(10 \leqslant p \leqslant 15\) or \(10 \lt p \lt 15\) or \(10 \leqslant p \lt 15\) or 10 – 15
Mark scheme (b) Scheme Marks 12.5 × 18 + 17.5 × 16 + 22.5 × 14 + 27.5 × 8 + 32.5 × 4 (= 1170) or 225 + 280 + 315 + 220 + 130 (= 1170) [lower bound products are: 180, 240, 280, 200, 120] [upper bound products are: 270, 320, 350, 240, 140] Sum of lower bound products = 1020 Sum of upper bound products = 1320 Sum of products using 11, 16, 21, 26 and 31 = 1080 Sum of products using 12, 17, 22, 27 and 32 = 1140 Sum of products using 13, 18, 23, 28 and 33 = 1200 Sum of products using 14, 19, 24, 29 and 34 = 1260 M2 “1170” ÷ 60 M1 Correct answer scores full marks (unless from obvious incorrect working) Answer: 19.5A1 (4) (5 marks)
Notes M2: for at least 4 correct products added (need not be evaluated) or If not M2 then award: M1 for consistent use of value within interval (including end points) for at least 4 products which must be added or correct midpoints used for at least 4 products and not added
M1: dep on at least M1 Allow division by their \(\Sigma f\) provided addition or total under column seen
A1: oe
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