Question 1

Paper 1Easy6 marks

A running coach records the weekly training time, xx hours, and 5 km race time, yy minutes, for six runners.

xx2457910
yy31.829.428.726.325.523.9
(a)

Use your graphic display calculator to find Pearson’s product-moment correlation coefficient, rr Give your answer to three significant figures.

[1]
(b)

Describe the direction and strength of the correlation.

[1]
(c)

Use your graphic display calculator to find the equation of the regression line of yy on xx in the form y=ax+by=ax+b Give the values of aa and bb to three significant figures.

[2]
(d)

Use the regression line to estimate the 5 km race time for a runner who trains for 6.5 hours per week. Give your answer to three significant figures.

[1]
(e)

Interpret the value of aa in this context.

[1]

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