Resolution:
## Figure 3.
Scatterplot matrix between all pairs of variables: age (years), CVLT free recall long
delay (number of correct items), intracranial volume (ICV) in mmOn the diagonal panels estimated probability density are given for each variable,
together with measurement value for each observation, the latter in the form of vertical
lines along the x-axis. The numerical range for each variable is given along both
the horizontal and the vertical borders of the matrix plot. The off-diagnal panels
allow for each variable to be compared to any other variable, interchanging the ordinate
and the abscissa. For each of these bivariate scatterplots a least square linear regression
line is fitted. Elliptic data-concentration contours for the fitted bivariate normal
distribution are also plotted. For highly correlated data the elliptic shape is elongated,
and for uncorrelated data the shape is circular. The contours are plotted at levels
0.5 and 0.9, i.e. 50% of the data is within the inner ellipse, and 90% within the
outer one. (The figure was produced by the car package in R.)
^{3}, hippocampus volume (ICV-normalized), total volume of cerbral cortex (ICV-normalized),
and total volume of lateral ventricles (ICV-normalized). Ystad |