A garden centre records the age, $x\,$ weeks, and the height, $y\,$ cm, of each of 20 seedlings of the same variety. The ages in the sample range from 2 weeks to 9 weeks.

The product moment correlation coefficient between $x\,$ and $y\,$ is 0.94, and the regression line of $y\,$ on $x\,$ for these data is

$y = 3.1 + 2.4 x$

Interpret the value 3.1 in this model, and state, with a reason, whether it is reliable.

A seedling of this variety is 18 cm tall. A student estimates its age as $18−3.12.4=6.2\dfrac{18 - 3.1}{2.4} = 6.2$ weeks. Give one reason why using this equation is not a sound way to estimate the age.

Explain why this model should not be used to estimate the height of a seedling of this variety at 30 weeks.

A garden centre records the age, $x\,$ weeks, and the height, $y\,$ cm, of each of 20 seedlings of the same variety. The ages in the sample range from 2 weeks to 9 weeks.

The product moment correlation coefficient between $x\,$ and $y\,$ is 0.94, and the regression line of $y\,$ on $x\,$ for these data is

$y = 3.1 + 2.4 x$

Interpret the value 3.1 in this model, and state, with a reason, whether it is reliable.

Explain why this model should not be used to estimate the height of a seedling of this variety at 30 weeks.

2.2.2 Scatter diagrams and correlation

Question 63

Markscheme

2.2.2 Scatter diagrams and correlation

Question 63

Markscheme

2.2.2 Scatter diagrams and correlation

Question 63

2.2.2 Scatter diagrams and correlation Questions

2.2.2 Scatter diagrams and correlation

Question 63

2.2.2 Scatter diagrams and correlation Questions