Question 3 The Office for National Statistics publishes the average price per litre in pence of ultra low sulphur/unleaded petrol (www.ons.gov.uk/economy/inflationandpriceindices/timeseries/czmk/mm23). The Minitab worksheet petrol.mwx contains the data for 2021 and

has two columns. The column month gives the survey month where January is month 1. The column price2021 gives the average price in pence per litre in the year 2021.