Session Ready
Exercise

Fitting a trend surface

The acidity data shows pH broadly increasing from north-east to south-west. Fitting a linear model with the coordinates as covariates will interpolate a flat plane through the values.

Instructions
100 XP

The acidity survey data, ca_geo has been pre-defined.

  • The response, on the left of the ~ sign, is the name of the column we are modeling.
  • The explanatory variables are on the right of the ~ sign, separated by a + sign, and are the names of the coordinate columns obtained by coordnames().
  • Fit the model and see if the model parameters are significant by seeing stars in the coefficients table.
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