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2.2.2 Scatter diagrams and correlation

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Question 25

A chemical engineer is investigating the relationship between the temperature of a solvent, TTT (in ∘C^\circ\text{C}∘C), and the mass of a specific solute that dissolves in it, ddd (in grams). A random sample of 15 trials was conducted, and the following summary statistics were recorded:

∑T=975∑T2=64125∑d=420Sdd=560∑Td=27930 \sum T = 975 \quad \sum T^2 = 64125 \quad \sum d = 420 \quad S_{dd} = 560 \quad \sum Td = 27930 ∑T=975∑T2=64125∑d=420Sdd​=560∑Td=27930
a.

Find the values of STTS_{TT}STT​ and STdS_{Td}STd​.

[2]
b.

Calculate, to 3 significant figures, the product moment correlation coefficient between TTT and ddd.

[2]
c.

The engineer also measured the viscosity of the solvent, vvv, during these 15 trials. The product moment correlation coefficient between TTT and vvv was found to be −0.552-0.552−0.552.

Describe, giving a reason, the nature of the correlation you would expect to find between vvv and ddd.

[2]

2.2.2 Scatter diagrams and correlation Questions

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  3. /2.2.2 Scatter diagrams and correlation