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chi-square tests

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Journal Article

Use of the chi-square test for the analysis of orientation data

C. K. Ballantyne, R. Cornish
Published: 01 September 1979
Journal of Sedimentary Research (1979) 49 (3): 773–776.
DOI: https://doi.org/10.1306/212F7842-2B24-11D7-8648000102C1865D
...C. K. Ballantyne; R. Cornish Abstract The chi-square test has been extensively employed by geologists and geomorphologists as a measure of the strength or statistical significance of preferred trends within orientation data. The x 2 value obtained is dependent on arbitrary selection of the pattern...
View PDF for article title, Use of the <span class="search-highlight">chi</span>-<span class="search-highlight">square</span> <span class="search-highlight">test</span> for the analysis of orientation data
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Histograms for comparisons used in Chi-square tests of independence for A) Stegoceras and Hanssuesia domes, comparing shape with upstream orientation and B) resting orientations versus shape; C) Pachycephalosaurus and Hanssuesia domes, comparing shape with upstream orientation and D) resting orientation versus shape; E) Stegoceras skull and isolated domes, comparing shape with upstream orientation and F) resting orientations versus shape.

Histograms for comparisons used in Chi-square tests of independence for A) ...

Published: 01 May 2013
FIGURE 5— Histograms for comparisons used in Chi-square tests of independence for A) Stegoceras and Hanssuesia domes, comparing shape with upstream orientation and B) resting orientations versus shape; C) Pachycephalosaurus and Hanssuesia domes, comparing shape with upstream orientation
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Table 3. Results of chi-square tests comparing empirical FAD and LAD frequ...

Published: 01 January 2001
Table 3. Results of chi-square tests comparing empirical FAD and LAD frequencies with mean simulated frequencies of a constant-turnover model and of pulsed models in which the background turnover rate was increased by three times and five times during two turnover pulses
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RESULTS OF CHI SQUARE TESTS

Published: 01 February 1961
T able I. RESULTS OF CHI SQUARE TESTS
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TABLE 2 —Results of Chi-square test of several biostratinomic variables for...

Published: 01 January 2009
TABLE 2 —Results of Chi-square test of several biostratinomic variables for two vertebrate fossil assemblages
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Values for the maximum likelihood (ML) chi-square test and log odds ratio. ...

Published: 01 November 2020
Table 2. Values for the maximum likelihood (ML) chi-square test and log odds ratio. Calculated from 2 × 2 contingency tables of traits of extant species that have a fossil record within or missing from Nukumaruan (2.4 Ma) and Castlecliffian (1.63 Ma) to recent. None of the p- values
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Results of ANOVA and Chi-squared tests for combined fern and seed fern grou...

Published: 01 March 2016
Table 3.— Results of ANOVA and Chi-squared tests for combined fern and seed fern groups. Significant p-values (α = 0.05) shown in bold .
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Chi-square test ρ values for comparisons of the distribution of specific da...

Published: 01 July 2014
Table 6.— Chi-square test ρ values for comparisons of the distribution of specific damage and encrustation levels, shell wear, and organism maturity in Nautilus assemblages from Bays 1–3 and the 2008 collection. Bold values indicate that the assemblage is significantly different (ρ < 0.05).
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ETAS model parameter estimates, log-likelihood, AIC and chi-square test res...

Published: 01 January 2013
Table II ETAS model parameter estimates, log-likelihood, AIC and chi-square test results for four triggering functions. Γ ( p ) stands for the value at point p of the Gamma function.
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Results of chi-squared test of thickness ratios of shell whorls for Damesit...

Published: 01 July 2012
T able 2 Results of chi-squared test of thickness ratios of shell whorls for Damesites sugata in the intervals with different shell diameters. N = number of specimens; SD = standard deviations; DF = the degrees of freedom; ns = not significant ( P >0.05).
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Results of chi-squared test of ammonitella diameters for Damesites sugata, ...

Published: 01 July 2012
T able 3 Results of chi-squared test of ammonitella diameters for Damesites sugata, Hypophylloceras subramosum, and Gaudryceras tenuiliratum. N = number of specimens; SD = standard deviations; DF = the degrees of freedom; ns = not significant ( P >0.05).
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Table 1. Chi-squared tests of distribution of fish species in the functiona...

Published: 01 August 2010
Table 1. Chi-squared tests of distribution of fish species in the functional morphospace biplot. “Total” refers to distribution across all four quadrants, “Orbit grad.” to distribution between the upper and lower halves and “LJ grad.” to distribution between the left and right halves. The expected
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Table 4. Results of chi-square test of observed versus expected endoskeleto...

Published: 01 January 2010
Table 4. Results of chi-square test of observed versus expected endoskeletobiont and predation trace occurrences. A p -value < 0.05 indicates either more or less biological activity in that shell region than expected, as indicated.
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TABLE 2—Chi-square test contingency tables for water pH, the du ration of a...

Published: 01 August 2005
TABLE 2—Chi-square test contingency tables for water pH, the du ration of acid treatment, burial depth, and acid-buffering capacity. The tables test the null hypothesis that the experimental variable is inde pendent of carapace recovery
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Age spectra of the subpopulations passing the chi-square test. The euhedral and rounded aliquots gave nearly identical subpopulations.

Age spectra of the subpopulations passing the chi-square test. The euhedral...

Published: 01 July 2001
Figure 7 Age spectra of the subpopulations passing the chi-square test. The euhedral and rounded aliquots gave nearly identical subpopulations.
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Ages of the crystal populations grouped according to the chi-square test. P...

Published: 01 July 2001
Table 2 Ages of the crystal populations grouped according to the chi-square test. P(Χ 2 ) is the probability of obtaining Χ 2 value for n degrees of freedom (where n = no. of crystals − 1; Galbraith 1981 ). The "binomfit" populations were determined by Mark Brandon's computer program. The two
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Table 3.  Summary statistics of contingency tables testing the independence...

Published: 01 January 2001
Table 3.  Summary statistics of contingency tables testing the independence of extinction with regard to taxonomy. df represents degrees of freedom in chi-squared tests; p represents significance level found with chi-squared test; F represents significance level found with Fisher's exact test
Journal Article

QUANTITATIVE SLOPE ANALYSIS

ARTHUR N STRAHLER
Journal: GSA Bulletin
Published: 01 May 1956
GSA Bulletin (1956) 67 (5): 571–596.
DOI: https://doi.org/10.1130/0016-7606(1956)67[571:QSA]2.0.CO;2
... of sampling points by drawing random pairs of rectangular coordinates; (2) use of sampling points uniformly spaced on a rectangular grid. A test area of about 1 square mile was selected near the center of the Emporium, Pennsylvania, topographic quadrangle. Population parameters of tangent of slope were...
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Journal Article

The mechanics of locating earthquakes

Ray Buland
Published: 01 February 1976
Bulletin of the Seismological Society of America (1976) 66 (1): 173–187.
DOI: https://doi.org/10.1785/BSSA0660010173
... errors of the parameters. The location parameters are found to be distributed as one minus chi squared with m degrees of freedom, where m is the number of parameters, allowing the simple construction of confidence levels. The use of the chi-squared test with n-m degrees of freedom, where n is the number...
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Journal Article

Determination of Flow Direction of Rhyolitic Ash-Flow Tuffs from Fluidal Textures

WOLFGANG E ELSTON, EUGENE I SMITH
Journal: GSA Bulletin
Published: 01 November 1970
GSA Bulletin (1970) 81 (11): 3393–3406.
DOI: https://doi.org/10.1130/0016-7606(1970)81[3393:DOFDOR]2.0.CO;2
... primary flowage. The statistical significance of results is documented by the Tukey Chi-square test and the vector method. Statistical parameters for these two techniques were calculated by Fortran IV program. Only seven samples (9 percent) indicated Chi-square values below the 90 percent confidence limit...
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