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

Question id: 362. This question is similar to one that appeared on an IB Standard paper in 2018. The use of a calculator is allowed.

The following table shows the mean weight in kilograms of members of a group of young children of various ages.

Age (x years) | 1.6 | 2.5 | 3.3 | 4.4 | 5.6 |
---|---|---|---|---|---|

Weight ( y kg) | 12 | 15 | 16 | 17 | 20 |

The relationship between the variables is modelled by the regression line with equation \(y = ax + b\)

(a) Find the value of \(a\) and of \(b\)

(b) Write down the correlation coefficient.

(c) Use your equation to estimate the mean weight of a child that is four years old.

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If you need more practice try the self-checking interactive exercises called Correlation.

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