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Wyświetlanie 1-2 z 2
Tytuł:
Triads or tetrads? Comparison of two methods for measuring the similarity in preferences under incomplete block design
Autorzy:
Zaborski, Artur
Powiązania:
https://bibliotekanauki.pl/articles/2108189.pdf
Data publikacji:
2022-09-14
Wydawca:
Główny Urząd Statystyczny
Tematy:
measurement of preferences
triads
tetrads
multidimensional scaling
Opis:
The measurement of preferences can be based on historical observations of consumer behaviour or on data describing consumer intentions. In the latter case, the measure-ment of preferences is performed using methods which express consumer attitudes at the time of research. However, most of these methods are very laborious, especially when a large number of objects is tested. In such cases incomplete analyses may prove useful. An incomplete analysis involves the division of objects into subgroups, so that each pair of objects appears at exactly the same frequency and all objects are in each subgroup. The purpose of the work is to compare two incomplete methods for measuring the similarity of preferences, i.e. the triad method and the tetrad method. These methods can be used whenever similarities are measured on an ordinal scale. They have been com-pared in terms of their labour intensity and ability to map the known structure of ob-jects, even when all pairs of objects in subgroups cannot be presented equally frequent-ly.
Źródło:
Statistics in Transition new series; 2022, 23, 3; 185-198
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Proliferation of abnormal palynoflora during the end-Devonian biotic crisis
Autorzy:
Filipiak, P.
Racki, G.
Powiązania:
https://bibliotekanauki.pl/articles/2059045.pdf
Data publikacji:
2010
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Devonian-Carboniferous transition
mutation
palynomorphs
tetrads
mass extinction
volcanism
Opis:
The dispersed miospore assemblage of the Retispora lepidophyta-Verrucosisporites nitidus (LN) Zone from the Holy Cross Mountains(Poland) is marked by enrichment (above 4%) in abnormal spore morphotypes during a terrestrial flora turnover close to the Devonian-Carboniferous boundary, recorded just above the Hangenberg Black Shale level. Incomplete and complete tetrads represent mostly Vallatisporites spp., supplemented by Grandispora, Retusotriletes and Apiculiretusispora. Additional peculiar morphotypes, marked byanomalous overall shape and ornamentation, are interpreted as mutated varieties of Vallatisporites based on intermediate morphologicalstages, connecting them with this well known genus. This relatively high aberrant palynomorph frequency is accompanied by volcanicash intercalations, as well as by charcoal debris and polycyclic aromatic biomarkers indicative of forest wildfire. Thus, the anomalousspore morphology could reflect the mutagenic effect of regional acidification due to explosive volcanism. However, palynological literature data from NW France and Canada highlight the possibility of a supra-regional mutated miospore signal near the Devonian-Carboniferous boundary, and there is need for high-resolution studies of the LN Zone to examine this. The end-Permian scenario of abnormalfloral growth in immensely stressed habitats may therefore apply to other potentially volcanically-induced biotic turnovers.
Źródło:
Geological Quarterly; 2010, 54, 1; 1-14
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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