June 2023 Paper 2 Q9

OCR MEICurrent spec5 marksIncludes samplingData ProcessingLarge Data Set

9 The pre-release material contains information concerning the median income of taxpayers in different areas of London. Some of the data for Camden is shown in the table below. The years quoted in this question refer to the end of the financial years used in the pre-release material. For example, the year 2004 in the table refers to the year 2003/04 in the pre-release material.

Year20042005200620072008200920102011
Median Income in £21 30023 20024 20025 90026 900#N/A28 40029 400
(a) Explain whether these data are a sample or a population of Camden taxpayers. [1]

A time series for the data is shown below.

Time series titled Median income of taxpayers in Camden 2004–2011: median income in pounds (0 to 35 000) against year (2003 to 2012), points for 2004 to 2008, 2010 and 2011 rising from about 21 300 to 29 400, with no point for 2009

The LINEST function on a spreadsheet is used to formulate the following model for the data:

\(I = 1115Y - 2\,212\,950\), where \(I =\) median income of taxpayers in £ and \(Y =\) year.

(b) Use this model to find an estimate of the median income of taxpayers in Camden in 2009. [1]
(c) Give two reasons why this estimate is likely to be close to the true value. [2]

The median income of taxpayers in Croydon in 2009 is also not available.

(d) Use your knowledge of the pre-release material to explain whether the model used in part (b) would give a reasonable estimate of the missing value for Croydon. [1]
‹ Previous33 of 43 in Data ProcessingNext ›