An ecologist is studying the effect of soil salinity, $s\,$ mS/cm, on the maximum growth height, $h\,$ cm, of a marsh grass. She records $s\,$ and $h\,$ at each of 10 sites and plots the data on a scatter diagram.

For 9 of the sites the points show a strong negative linear correlation, and the product moment correlation coefficient for those 9 sites is -0.824.

The 10th site, Site Omega, is plotted at $82)(48,\ 82)$ , which lies well above the trend shown by the other 9 sites.

State why Site Omega might be considered an outlier in this context.

State, giving a reason, what effect including Site Omega would have on the value of the product moment correlation coefficient.

The ecologist decides to delete Site Omega before fitting a model. Give one argument in favour of deleting it and one argument against.

For 9 of the sites the points show a strong negative linear correlation, and the product moment correlation coefficient for those 9 sites is -0.824.

The 10th site, Site Omega, is plotted at $82)(48,\ 82)$ , which lies well above the trend shown by the other 9 sites.

State why Site Omega might be considered an outlier in this context.

State, giving a reason, what effect including Site Omega would have on the value of the product moment correlation coefficient.

The ecologist decides to delete Site Omega before fitting a model. Give one argument in favour of deleting it and one argument against.

2.2.2 Scatter diagrams and correlation

Question 15

Markscheme

2.2.2 Scatter diagrams and correlation

Question 15

Markscheme

2.2.2 Scatter diagrams and correlation

Question 15

2.2.2 Scatter diagrams and correlation Questions

2.2.2 Scatter diagrams and correlation

Question 15

2.2.2 Scatter diagrams and correlation Questions