Edexcel IAL S1 June 2022 mark scheme and question paper (WST01/01)

3 S1 questions like these, with worked solutions

Written and checked by us, not taken from the Pearson paper. Try each one, then tap "Worked solution" to see every step and its marks.

1. Representation of Data · 5 marks

   The data in a histogram is grouped into classes. A bar representing the class $100\le x<150$ has a width of $2.5\text{ cm}$ and a height of $4\text{ cm}$. The total area of all bars in the histogram is $90{\text{ cm}}^2$. If the bar for $100\le x<150$ represents a frequency of $20$, calculate the total frequency of the entire data set.

   Worked solution

   1. M1 for calculating the area of the specified bar: $2.5\times 4=10{\text{ cm}}^2$.
   2. M1 for establishing the relationship between area and frequency: $10{\text{ cm}}^2$ represents a frequency of $20$.
   3. A1 for calculating the scale factor: $1{\text{ cm}}^2$ represents $2$ items (since $20/10=2$).
   4. M1 for using the total area to find total frequency: $90{\text{ cm}}^2\times 2$.
   5. A1 for the final answer: $180$ items.

2. Probability · 3 marks

   Three independent events $A$, $B$, and $C$ have probabilities $P(A)=0.5$, $P(B)=0.4$, and $P(C)=0.3$. Find the probability that exactly one of these events occurs.

   Worked solution

   1. M1 for identifying the three scenarios: $(A\cap B^{\prime }\cap C^{\prime })$, $(A^{\prime }\cap B\cap C^{\prime })$, and $(A^{\prime }\cap B^{\prime }\cap C)$.
   2. M1 for calculating the probabilities of these scenarios: $(0.5\times 0.6\times 0.7)+(0.5\times 0.4\times 0.7)+(0.5\times 0.6\times 0.3)$.
   3. A1 for evaluating and summing: $0.21+0.14+0.09=0.44$.

3. Discrete Random Variables · 4 marks

   The discrete random variable $X$ takes the values $1,2,$ and $3$ with probabilities $a,b,$ and $0.3$ respectively. Given that $E(X)=1.9$, find the values of $a$ and $b$.

   Worked solution

   1. M1 for forming the sum of probabilities equation: $a+b+0.3=1⟹a+b=0.7$.
   2. M1 for forming the expected value equation: $1(a)+2(b)+3(0.3)=1.9⟹a+2b=1.0$.
   3. M1 for solving the simultaneous equations (e.g., subtracting the first from the second: $b=1.0-0.7$).
   4. A1 for concluding $b=0.3$ and $a=0.4$.

More on these topics: Representation of Data · Probability · Discrete Random Variables

What's on this paper

What this paper is like

• Shape: 6 questions, 75 marks in 1 h 30 min (about 1.2 minutes a mark); questions from 11 to 14 marks.
• Biggest question: Q2, 14 marks: gDP data: correlation and regression.
• Marks by main topic: Correlation and Regression 14, Representation of Data 14, Discrete Random Variables 14, Measures of Location and Spread 11, Probability 11, Normal Distribution 11.
• More Correlation and Regression in other sittings: October 2022 Q2 (13 marks), January 2022 Q6 (13 marks), January 2023 Q6 (14 marks).
• Against the other 14 sittings we mapped: more marks on Measures of Location and Spread (11 marks here, 5 on average); fewer on Probability (11 marks here, 17 on average).
• Not on this paper: Data and Summary Statistics.
• Calculator: allowed.

WST01/01: question by question

Labels and topics are ours, read from the WST01/01 paper (checked 2026-11-01); marks as printed. Tap a number to practise that topic.

1. Q1Contractors' hours: mean and spread (11 marks) · S1 Measures of Location and Spread
2. Q2GDP data: correlation and regression (14 marks) · S1 Correlation and Regression
3. Q3Grouped log lengths: histogram and quartiles (14 marks) · S1 Representation of Data, S1 Measures of Location and Spread
4. Q4Events H and W: independence (11 marks) · S1 Probability
5. Q5Spinner scores: probability distribution (14 marks) · S1 Discrete Random Variables
6. Q6Normal model for oil in bottles (11 marks) · S1 Normal Distribution

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