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Volumes / Journal / 21 - 2010 / Baxter M., Cool H., Anderson M.

Statistical analysis of some loomweights from Pompeii: a postscript

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Fig. 1 – A KDE using all the weight data; the main modes are at 162 g and 293 g. Compare with Fig. 2 in BC08.

Fig. 1 – A KDE using all the weight data; the main modes are at 162 g and 293 g....

Fig. 2 – Height against weight labelled by “old” (o) or “new” (x).

Fig. 2 – Height against weight labelled by “old” (o) or “new” (x).

Fig. 3 – KDEs for the “old” (solid line) and “new” data (dashed line) for weight, from the modified data set. Modes are at 159 and 274 for the old data; and 162 and 301 for the new data. Sample sizes are 89 for the “old” data and 36 for the “new” data.

Fig. 3 – KDEs for the “old” (solid line) and “new” data (dashed line) for weight...

Fig. 4 – As Fig. 3, but for height. The modes are at 68 and 98 for the “old” and 69, 99 and 112 for the “new” data.

Fig. 4 – As Fig. 3, but for height. The modes are at 68 and 98 for the “old” and...

Fig. 5 – KDE for the volume data, using a subjectively determined bandwidth of 8000.

Fig. 5 – KDE for the volume data, using a subjectively determined bandwidth of 8...

Fig. 6 – A bivariate contour plot based on a two-dimensional kernel density estimate for the volume and weight data. The kde2 function from the MASS library in R was used, with bandwidths of 40000 and 100 suggested by the Sheather-Jones estimates for each variable separately. The dotted line shows the division into large and small suggested by Fig. 7.

Fig. 6 – A bivariate contour plot based on a two-dimensional kernel density esti...

Fig. 7 – Plot of estimated volume against height. The solid line is the regression line that can be used to predict weight from height; the horizontal dashed line shows the division into “large” and “small” weights suggested by an analysis of weight only; the dotted line is subjectively determined from this figure to suggest an alternative division into “large” and “small”.

Fig. 7 – Plot of estimated volume against height. The solid line is the regressi...

Fig. 8 – A plot of the maximum to minimum ratio of the tops of the loomweights against a similar ratio for the bottom of the loomweights; “old” data (o) and “new” data (x). See the text for further explanation. Compare BC08 Fig. 10.

Fig. 8 – A plot of the maximum to minimum ratio of the tops of the loomweights a...

Baxter M., Cool H., Anderson M. 2010, Statistical analysis of some loomweights from Pompeii: a postscript, Archeologia e Calcolatori 21