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The last line of the display contains a quantity known as twice the log likelihood. This will prove to be useful in comparing alternative models for the data and carrying out significance tests. It can be ignored for the time being. This is another place where you would do well to save the worksheet. Graphing Predictions : Variance components We have now constructed and fitted a variance components model in which schools vary only in their intercepts. It is a model of simple variation at level 2, which gives rise to the parallel lines illustrated in figure 1.2. To demonstrate how the model parameters we have just estimated combine to produce the parallel lines of figure 1.2 we now introduce two new windows the Predictions window that can be used to calculate predictions from the model and the Customised graphs window which is a general purpose window for building graphs that can be used to graph our predicted values. Lets start by calculating the average predicted line produced from the fixed part intercept and slope coefficients( β 0 , β 1 ). Select the Model menu Select Predictions Which produces : 15