June 2025 Paper 2 Q10

OCR MEICurrent spec5 marksData ProcessingLarge Data Set

10 The pre-release material contains information about life expectancy at birth for countries of the world at 10-year intervals from 1960 until 2020.

The life expectancy at birth of the population of Sudan for this period, together with a line of best fit, is shown in Fig. 10.1.

Fig. 10.1: life expectancy at birth in Sudan plotted against year from 1960 to 2020, rising from about 48 to about 65, with a dotted line of best fit
Fig. 10.1

The equation of the line of best fit is \(L = 0.275X - 490\), where \(X\) is the year and \(L\) is the life expectancy at birth, measured in years.

(a) Use the equation of the line of best fit to estimate the life expectancy at birth in Sudan in 1975. [1]
(b) Explain whether this estimate is likely to be close to the true value of life expectancy at birth in Sudan in 1975. [1]
(c) Use your knowledge of the pre-release material to explain whether your answer to part (a) is likely to be a close approximation to the life expectancy at birth in the United Kingdom in 1975. [1]

The pre-release material also gives the median age of the population in countries of the world.

The table shows the median age of the population and the life expectancy at birth in 2020 for some countries in Africa.

CountryMedian ageLife expectancy at birth 2020
Nigeria18.655.02
Rwanda19.769.33
Saint Helena, Ascension and Tristan da Cunha43.2#N/A
Sao Tome and Principe19.370.58
Senegal19.468.21
(d) Explain how the data in the table should be cleaned before these data can be included in a scatter diagram for life expectancy at birth against median age for the countries in Africa. [1]

Fig. 10.2 shows a scatter diagram for the cleaned data of life expectancy at birth against median age in 2020 for the countries in Africa. It also shows a line of best fit.

The product moment correlation coefficient for these data is 0.680.

Fig. 10.2: scatter diagram of life expectancy at birth 2020 (L) against median age in 2020 (X) for African countries, median ages about 15 to 37, with a dotted line of best fit
Fig. 10.2
(e) A student decides to use the line of best fit to estimate the life expectancy at birth in 2020 for Saint Helena, Ascension and Tristan da Cunha.

Explain whether this estimate is likely to be reliable. [1]
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