a statistical analysis of gunther series projectile - Society for ...
a statistical analysis of gunther series projectile - Society for ...
a statistical analysis of gunther series projectile - Society for ...
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the classification <strong>of</strong> Gunther Contracting Stems at<br />
Sly Park. The test was implemented by running t<br />
tests <strong>for</strong> significant differences between the<br />
within-site means on individual metric characters.<br />
Sample size varied by measure because <strong>of</strong>missing<br />
values resulting from broken pieces. The <strong>analysis</strong><br />
included 34 points from Miller Mound and 35<br />
points from Sly Park.<br />
The results <strong>of</strong> the tests show that, <strong>for</strong> 12 out<br />
<strong>of</strong> 18 characters, there is no significant difference<br />
between the mean values <strong>of</strong> point measures from<br />
the two sites (Table 1). The mean values <strong>for</strong> most<br />
<strong>of</strong> these characters are very similar, and the<br />
probabilities <strong>of</strong> no significant difference are very<br />
high. Characters showing significant differences<br />
between the sites include thickness, and the related<br />
measures <strong>of</strong> neck width, notch width, distal stem<br />
width-to-neck width ratio, neck width-to-stem<br />
length ratio, and neck width-to-total width ratio.<br />
Sly Park points are significantly thicker. This<br />
is probably a result, however, <strong>of</strong> the fact that<br />
many <strong>of</strong> these points are made <strong>of</strong> chert and quartz,<br />
which frequently contains inclusions that <strong>for</strong>ce a<br />
thicker point. The Miller Mound points, by<br />
contrast, are mostly made <strong>of</strong> obsidian and a fmegrained<br />
basalt. This is not a character, in other<br />
words, which has to do with aspects <strong>of</strong> intentional<br />
point shaping.<br />
The Sly Park points have significantly wider<br />
notches and necks than Miller Mound, and this is<br />
reflected in ratios including these measures. This<br />
means that, though the points are the same in<br />
terms <strong>of</strong> all other shape and size characters, Miller<br />
Mound Gunther Contracting Stem points tend to<br />
have straighter, or less v-shaped stems than those<br />
from Sly Park.<br />
Though there is significant variation between<br />
the two sites in terms <strong>of</strong> stem shape, in general, it<br />
is reasonable to conclude Gunther Contacting<br />
Stem points from the two locations belong to the<br />
same population in terms <strong>of</strong> all other size and<br />
shape characters.<br />
Validity <strong>of</strong> the Sutter Variant<br />
The second step in the research design is the<br />
test to determine whether the points intuitively<br />
classified as Sutter Variant at Sly Park are significantly<br />
different from Gunther Contracting Stem<br />
points at Miller Mound and Sly Park combined.<br />
The test was implemented by running t-tests <strong>for</strong><br />
significant differences between the within-type<br />
means on individual metric characters. Sample<br />
size varied by measure because <strong>of</strong> missing values<br />
resulting from broken pieces. The <strong>analysis</strong> included<br />
69 Gunther Contracting Stem points and<br />
23 Sutter Variant points.<br />
The results <strong>of</strong> the tests show that, <strong>for</strong> II out<br />
<strong>of</strong> 18 the characters measured, there is a significant<br />
difference between the Sutter Variant and<br />
Gunther Contracting Stem (Table 2). The Gunther<br />
points are significantly longer, wider, and<br />
heavier, than Sutter Variants. The Gunther stems<br />
and notches are wider and longer. The Sutter<br />
points, on the other hand, have a significantly<br />
larger length-to-width ratio. They are somewhat<br />
longer/narrower in shape. Sutter points also have<br />
a significantly shorter stem in relation to length<br />
and a larger ratio <strong>of</strong> neck to maximum width. The<br />
stem is also narrower at its end, in relation both to<br />
maximum length and to neck width, than the<br />
Gunther point stem.<br />
In general, the intuitive impression <strong>of</strong> the<br />
Sutter Vanant as a gracile Gunther Contracting<br />
stem, slightly narrower, and with a smaller, more<br />
tapering stem, is confirmed by these results. The<br />
most obvious difference, however, is one <strong>of</strong> scale.<br />
Most <strong>of</strong> the scale measurements (weight, length,<br />
width) show a significant difference, and some<br />
shape measurements do not (such as proximal<br />
shoulder angle, distal shoulder angle, and notch<br />
angle). In sum, the Sutters are smaller than<br />
Gunthers, and have clear, but subtle shape differences<br />
involving the shape <strong>of</strong> the stem and the<br />
overall length-width proportions.<br />
Discriminant Analysis<br />
The purpose <strong>of</strong> the discriminant <strong>analysis</strong> is to<br />
calculate a discriminant function that is a linear<br />
combination <strong>of</strong> individual measures and which<br />
provides the maximum possible separation be<br />
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