Quick questions on Correlation and regression explained: H2 Mathematics Probability and Statistics

5short Q&A pairs drawn directly from our worked dot-point answer. For full context and worked exam questions, read the parent dot-point page.

What is the product moment correlation coefficient?

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The coefficient

r

measures the strength and direction of a linear relationship between two variables, taking values in

-1 \leq r \leq 1

What is the least squares regression line?

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The least squares regression line of

y

x

minimises the sum of squared vertical distances from the points to the line. It passes through the mean point

(\bar{x}, \bar{y})

and has the form

What is q1?

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Interpret a correlation coefficient of

r = -0.91

. [2 marks]

What is q2?

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A regression line of

y

x

y = 1 + 2x

. Predict

y

when

x = 3

. [1 mark]

What is q3?

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Explain why extrapolation can give unreliable predictions. [2 marks]

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