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2.5 Data presentation and interpretation

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Question 62

The dissolved oxygen concentration, DDD (mg/L), and the water temperature, TTT (∘^{\circ}∘C), were measured at n=12n = 12n=12 distinct sampling stations in a hydro-thermal basin.

Some of the summary statistics for these measurements are given below:

∑T=108∑T2=1119SDD=75.0STD=−78.5 \sum T = 108 \quad \sum T^2 = 1119 \quad S_{DD} = 75.0 \quad S_{TD} = -78.5 ∑T=108∑T2=1119SDD​=75.0STD​=−78.5
a.

(i) Calculate the mean of the 12 recorded values of TTT.

(ii) Show that the standard deviation of the 12 values of TTT is 3.503.503.50 to 3 significant figures.

[3]
b.

Calculate the product moment correlation coefficient (PMCC) between TTT and DDD.

[3]
c.

To standardize the data for an international report, the temperature values were converted using the linear transformation W=1.5T+12W = 1.5T + 12W=1.5T+12.

Use your results from part (a) to calculate the mean and the standard deviation of the transformed values, WWW.

[2]
d.

Given that VVV is the equivalent transformed value of DDD using the same linear coding V=1.5D+12V = 1.5D + 12V=1.5D+12, state the value of the product moment correlation coefficient between WWW and VVV. Give a reason for your answer.

[2]

2.5 Data presentation and interpretation Questions

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