## Exam-Style Question on Correlation## A mathematics exam-style question with a worked solution that can be revealed gradually |

Question id: 84. This question is similar to one that appeared on an IB Studies paper in 2014. The use of a calculator is allowed.

The following table shows the relationship between the number of workers and the amount of time in minutes it takes them to harvest the sugar cane in a particular field.

Workers (\(n\)) | Time (\(t\)) |
---|---|

3 | 799 |

4 | 703 |

5 | 645 |

6 | 570 |

8 | 422 |

9 | 322 |

10 | 241 |

(a) Find the equation of the regression line of \(t\) on \(n\).

(b) Find the value of the Pearsonâ€™s productâ€“moment correlation coefficient, r.

(c) Use the regression equation to find how long it would take seven workers to harvest the sugar cane.

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