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Estimation Using Confidence Intervals
Published in William M. Mendenhall, Terry L. Sincich, Statistics for Engineering and the Sciences, 2016
William M. Mendenhall, Terry L. Sincich
Teeth defects and stress in prehistoric Japan. Linear enamel hypoplasia (LEH) defects are pits or grooves on the tooth surface that are typically caused by malnutrition, chronic infection, stress and trauma. A study of LEH defects in prehistoric Japanese cultures was published in the American Journal of Physical Anthropology (May 2010). Three groups of Japanese people were studied: Yayoi farmers (early agriculturists), eastern Jomon foragers (broad-based economy), and western Jomon foragers (wet rice economy). LEH defect prevalence was determined from skulls of individuals obtained from each of the three cultures. The results (percentage of individuals with at least one LEH defect) are provided in the accompanying table. Two theories were tested. Theory 1 states that foragers with a broad-based economy will have a lower LEH defect prevalence than early agriculturists. Theory 2 states that foragers with a wet rice economy will not differ in LEH defect prevalence from early agriculturists.
Oral health of the prehistoric Rima Rau cave burials, Atiu, Cook Islands
Published in Journal of the Royal Society of New Zealand, 2020
Angela L. Clark, Christina Stantis, Hallie R. Buckley, Nancy Tayles
Five individuals (5/12, 41.7%) had localised defects observable in only one tooth. For two of these individuals, the defects were singular linear enamel hypoplasia (LEH), the defects in two other individuals were discrete opacities in a single tooth, and one individual had one tooth with a diffuse opacity. Due to issues of preservation, wear and only considering mandibular teeth in the individual analysis, prevalence rates of localised enamel defects may not precisely reflect the frequency of traumatic events resulting in localised defects. For example, the single LEH defect in two of the five individuals may have resulted from systemic stress, rather than trauma. However, this cannot be determined with certainty due to a lack of defects in the rest of the mandibular dentition, but perhaps could have been resolved if corresponding maxillary teeth were observed.