Statistical assessment of population variability: a methodological approach

Area of Science:

• Bioarchaeology
• Paleopathology
• Statistical Anthropology

Background:

• Assessing cranial variability is crucial for understanding population dynamics and social structures in past communities.
• Skeletal samples offer insights into group composition, health, and cultural practices.

Purpose of the Study:

• To implement and apply a multivariate statistical methodology for evaluating cranial variability in skeletal samples.
• To compare cranial variability within archaeological samples against a baseline of normal within-group variability.

Main Methods:

• Developed a statistical method comparing covariance matrices of skeletal samples.
• Applied the methodology to two Plains Indian craniometric datasets: Leavenworth site (39CO9) and Bad River 2 Phase sites.

Main Results:

• Substantial heterogeneity in cranial morphology was detected among crania from the Leavenworth site.
• Cranial heterogeneity at Leavenworth was partly explained by distinct burial areas, suggesting preserved social distinctions.
• No significant differentiation was found among sites within the Bad River 2 Phase, indicating a cohesive biological unit.

Conclusions:

• The multivariate statistical approach effectively identifies significant cranial heterogeneity within skeletal samples.
• Analysis of the Leavenworth site supports the interpretation of distinct social organization reflected in burial practices.
• The Bad River 2 Phase samples represent a biologically integrated population unit.