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2.2.2 Scatter diagrams and correlation

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Question 47

Mathematical models are frequently employed to interpret experimental data.

a.

Beyond being cost-effective and efficient, state two other advantages of using statistical models.

[2]
b.

A chemist is studying the relationship between the concentration of a catalyst, x x\,x mmol/L, and the rate of a specific chemical reaction, y y\,y units, at a constant low temperature.

A random sample of 10 observations was recorded and is shown in the table below.

Concentration (xxx)0.50.81.21.52.02.42.73.13.54.3
Reaction Rate (yyy)12.415.118.222.025.829.433.138.542.051.5

[You may use: ∑x=22\sum x = 22∑x=22, ∑y=288\sum y = 288∑y=288, ∑x2=61.98\sum x^2 = 61.98∑x2=61.98, ∑xy=772.45\sum xy = 772.45∑xy=772.45, Sxx=13.58S_{xx} = 13.58Sxx​=13.58]

Calculate the value of SxyS_{xy}Sxy​ for this dataset.

[2]
c.

Determine the equation of the regression line of y y\,y on x x\,x in the form y=a+bxy = a + bxy=a+bx. Give the values of a a\,a and b b\,b to 3 significant figures.

[3]
d.

Interpret the meaning of the constant b b\,b in the context of this study.

[1]
e.

Use your model to estimate the reaction rate when the concentration of the catalyst is 3.0 mmol/L.

[2]
f.

Comment on the reliability of using this specific regression model to predict the reaction rate in a high-temperature industrial environment.

[1]

2.2.2 Scatter diagrams and correlation Questions

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  3. /2.2.2 Scatter diagrams and correlation