October 2021 Paper 2 Q12

OCR MEICurrent spec7 marksData ProcessingLarge Data Set

12 Fig. 12.1 shows an excerpt from the pre-release material.

ABCDEFGH
1SexAgeMaritalWeightHeightBMIWaistPulse
2Female34Married60.3173.420.0582.574
3Female85Widowed64.7161.224.9#N/A#N/A
4Female48Divorced100.6171.434.24105.692
5Male61Married70.9169.524.6892.270
6Male68Divorced96.8181.629.35112.968

Fig. 12.1

There was no data available for cell H3.

(a) Explain why #N/A is used when no data is available. [1]

Fig. 12.2 shows a scatter diagram of pulse rate against BMI (Body Mass Index) for females.
All the available data was used.

Fig. 12.2: scatter diagram titled Pulse rate against BMI for females; BMI 0 to 50, pulse rate 0 to 140; most points have BMI 17 to 45 and pulse 44 to 106, with one point at about (1.3, 88) and one at about (30.6, 128)
Fig. 12.2

There are two outliers on the diagram.

(b) On the copy of Fig. 12.2 in the Printed Answer Booklet, ring these outliers. [1]
(c) Use your knowledge of the pre-release material to explain whether either of these outliers should be removed. [2]
(d) State whether the diagram suggests there is any correlation between pulse rate and BMI. [1]

The product moment correlation coefficient between waist measurement, \(w\), in cm and BMI, \(b\), for females was found to be 0.912. All the available data was used.

(e) Explain why a model of the form \(w = mb + c\) for the relationship between waist measurement and BMI is likely to be appropriate. [1]

The LINEST function on a spreadsheet gives \(m = 2.16\) and \(c = 33.0\).

(f) Calculate an estimate of the value for cell G3 in Fig. 12.1. [1]
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