Upotreba koeficijenata korelacije u procjeni podrijetla nitrata na području zagrebačkog vodonosnika

master's thesis

• Title: Upotreba koeficijenata korelacije u procjeni podrijetla nitrata na području zagrebačkog vodonosnika : diplomski rad
• Title (english): The use of correlation coefficients in assessing the origin of nitrate in the area of the Zagreb aquifer : master’s thesis
• Author: Martina Vulić
• Mentor: Zoran Nakić (mentor)
• Committee member: Zoran Nakić
• Committee member: Andrea Bačani
• Committee member: Jelena Parlov
• Granter: University of Zagreb; Faculty of Mining, Geology and Petroleum Engineering; (Department of Geology and Geological Engineering); Zagreb
• Defense date and country: 2015-12-11, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mining, Petroleum and Geology Engineering; Geological Engineering

Abstract

Zadnjih nekoliko desetljeća brojna istraživanja ukazala su na značajno onečišćenje podzemne vode nitratima. Glavni razlog vidljiv je u korištenju povišenih količina agrotehničkih sredstava, s ciljem povećanja proizvodnje hrane obzirom na stalni rast ljudske populacije.
Primjena koeficijenata korelacije jedna je od statističkih metoda kojom se može procjeniti podrijetlo nitrata u podzemnim vodama. U ovom radu korištena su dva koeficijenta korelacije, Pearsonov (parametarski) i Spearmanov (neparametarski). Podaci na kojima su se vršili izračuni prikupljani su sa 76 piezometara na području grada Zageba. Korišteni su podaci o koncentracijama nitrata (NO3-), klorida (Cl-) i natrija (Na+) u razdoblju od 1991.-2013. godine. Ispitivanje normalne raspodjele podataka, te njihove linearnosti, provedeno je izradom histograma, odnosno grafova linearnosti. Da bi se odredila statistička značajnost koeficijenata korelacije korišten je „t-test“. Kod manjeg broja podataka, za testiranje statističke značajnosti koriste se Pearsonova i Spearmanova tablica statističke značajnosti.
Provedene statističke metode sugeriraju organsko podrijetlo na 15 bušotina, no bez jednoznačnog odgovora o povezanosti koeficijenata korelacije s točnim podrijetlom nitrata.

Abstract (english)

Abstract: Over the last few decades numerous studies have pointed to the significant nitrate contamination of groundwater. The main reason is the use of increased amounts of agro-technical resources in order to increase food production due to the steady growth of the human population.
The use of correlation coefficients presents as one of the statistical methods that can determine the origin of nitrate in groundwater. Two correlation coefficients were used in this thesis; Pearson (parametric) and the Spearman (non-parametric). The data on which the calculations were performed had been collected from 76 piezometers in the area of the City of Zagreb. The data on concentrations of nitrate (NO3-), chloride (Cl-) and sodium (Na+) in the period from 1991 to 2013 had been used. The examination of the normal data distribution and their linearity was conducted by the creation of histograms and linearity graphs, respectively. In order to determine the statistical significance of the correlation coefficient the "t-test" was used. In case of less data, the Pearson and Spearman tables of statistical significance were used for testing the statistical significance.
Conducted statistical methods suggested an organic origin in 15 wells, but on the other hand they did not give a sufficiently clear response to the coherence of correlation coefficients with an exact origin of nitrates.

• Keywords: Podrijetlo nitrata; koeficijent korelacije; histogram; statistička značajnost; t-test
• Keywords (english): Nitrate origin; the correlation coefficient; histogram; statistical significance; t-test
• Language: croatian
• URN:NBN: urn:nbn:hr:169:836838
• Study programme: Title: Geological Engineering; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka geološkog inženjerstva (magistar/magistra inženjer/inženjerka geološkog inženjerstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2016-01-12 13:33:44