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2.5.10 Correlation as closeness to a straight line (A-level only)

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Question 25

A marine biologist investigates the relationship between the depth of water, ddd (in metres), and the concentration of dissolved oxygen, ccc (in mg/L), at 12 specific locations in a deep-sea trench. The following summary statistics were recorded from the collected data:

Sdd=840.5Scc=15.2Sdc=−102.4 S_{dd} = 840.5 \quad S_{cc} = 15.2 \quad S_{dc} = -102.4 Sdd​=840.5Scc​=15.2Sdc​=−102.4
a.

Calculate the product moment correlation coefficient (PMCC) for this set of data.

[3]
b.

Interpret the calculated PMCC value within the context of the marine biologist's investigation.

[2]
c.

The biologist later decides to convert the depth measurements from metres to centimetres by multiplying each ddd value by 100 and then adding a constant sensor offset of 5. Write down the value of the PMCC that would be obtained using these coded depth values and the original concentration values.

[1]

2.5.10 Correlation as closeness to a straight line (A-level only) Questions

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