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.

Question 6 The Office for National Statistics publishes the Retail Price Index (RPI) and related data (www.ons.gov.uk/economy/inflationandpriceindices). Price ratios and weights from the year 2020 are listed in Table 2. (The base date was January 1987.) (a) Why are pensioner households and high-income households excluded from the RPI? Justify your answer. (b) By considering the price ratio for 'Food and catering' in Table 2, comment on whether the food and catering prices in November 2020 have increased or decreased relative to January 2020. Justify your answer. (You do not need to calculate the percentage change.) (c) Using the data given in Table 2 (i) Show that the unrounded all-item price ratio for November 2020 relative to January 2020 is 1.009953. (ii) The value of the RPI in January 2020 was 290.6. Using the all-item price ratio given above in part (i), find the value of the RPI in November 2020 rounded to one decimal place. (d) An RPI index-linked pension was £733 per month in January 2020. The value of the RPI in January 2021 was 294.6. How much should the pension be per month in January 2021? Please give your answer rounded to the nearest pound. (e) Using relevant values of the RPI, calculate the purchasing power of the pound in January 2021 compared with the base date January 1987. Please give your answer rounded to the nearest penny.