Evidence is mounting that a part of the brain known as the hippocampus is crucial for tasks that depend on relating information from multiple sources, such as tasks requiring spatial memory. Broadbent et al. (2004) tested this experimentally by surgically inducing lesions of different extent in the hippocampus of rats and measuring the subsequent memory performance of the rats in a maze.

Their data are plotted in the accompanying graph.

a. Write a model statement for a linear model to fit to these data. Indicate what each term in the model represents.

b. Write the corresponding statement for the null model.

c. Using a ruler, add the predicted values for each model to the figure (approximate positions will suffice).

Transcribed Image Text:

Spatial memory score 20 15 10- 5 0 0 40 60 80 Extension of lesion (%) 20 100