1. 1
   A researcher records the number of pets owned by 20 households by visiting each household directly. The data (number of pets per household) is: 0, 1, 2, 1, 3, 0, 1, 2, 4, 1, 0, 2, 1, 3, 1, 0, 2, 1, 2, 1.

   (a)

   What type of data has the researcher collected?

   [1 mark]

   • ADiscrete primary data
   • BContinuous primary data
   • CDiscrete secondary data
   • DContinuous secondary data

   (b)

   Find the mode of the data.

   [1 mark]

   • A$3$
   • B$2$
   • C$0$
   • D$1$

   (c)

   Find how many households have more than 1 pet.

   [1 mark]

   • A$4$
   • B$8$
   • C$12$
   • D$9$

   Total for question 1: 3 marks

2. 2
   60 students were asked how they travel to school. 24 travel by car, 15 by bus, 9 walk, and the rest cycle.

   (a)

   Find the number of students who cycle to school.

   [2 marks]

   (b)

   A pie chart is to be drawn to represent this data. Find the angle that represents students who travel by bus.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A scientist records the temperature (°C) and the number of ice creams sold at a beach kiosk over 10 days. The scatter graph of this data shows a strong positive correlation.

   (a)

   State what is meant by "strong positive correlation" in this context.

   [3 marks]

   (b)

   Explain why this correlation does not necessarily mean that high temperatures cause more ice creams to be sold.

   [3 marks]

   Total for question 3: 6 marks

4. 4
   A market research company wants to find out how much monthly pocket money is received by teenagers in a city of 50,000 teenagers. They survey the first 200 teenagers who arrive at a shopping centre on a Saturday afternoon.

   (a)

   Explain one way in which this sampling method could produce biased results, and hence explain why the sample may not be representative of all teenagers in the city.

   [4 marks]

   (b)

   Suggest a more appropriate sampling method the company could use to obtain a representative sample of the 50,000 teenagers, and describe how it would work.

   [4 marks]

   (c)

   The company decides to use stratified sampling by age group (13-15, 16-17, 18-19) to select a sample of 300 teenagers from the city's 50,000 teenagers. Given that 21,000 of the teenagers are aged 13-15, find the number of 13-15 year olds that should be included in the sample.

   [5 marks]

   Total for question 4: 13 marks

End of questions