Statistical Analysis Stack Exchange
Statistical Analysis Stack Exchange

Questions tagged [environmental-data]

30 questions
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R vegan: RDA vs CCA, which test to answer my research question and which results to report?

(if my question should be cut up into sub-questions please let me know, since all those questions are related I decided to ask them here together as one long question) Main question As part of my research I try to perform multivariate analysis in…
Ciska
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Do I need to standardize environmental data before canonical correspondence analysis?

I have a dataset of 15 environmental variables (soil physical and chemical properties) and about 25 "species" variables for about 40 sampling sites. I want to do a CCA to analyse the effects of the environmental data on the species pattern. However,…
MMarton
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What to do if time series data remains autocorrelated?

Data: I have 92 years of monthly climate data. One of my variables is a drought index (SPEI) ranging from -2 (dry) to 2 (wet). All the data can be found here. Data Structure: year month order.ID season temp.avg ppt.avg GDD pdo …
theforestecologist
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Population genetics: analysis of allele frequency distribution along environmental gradients

Is there a software or a R package that does a simulation of spatial distribution of alleles? I'm interested in how a distribution of alleles of functional loci is shaped by a pattern of environmental variables, such as temperatures and water…
Young
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How to compute a measure of distance between sites with continuous variables?

I have a dataframe with each row being a different site (51 sites), and each column being mean values of a different continuous environmental variable (19 variables). I am trying to calculate a measure of environmental similarity/dissimilarity by…
user2224681
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How the kurtosis value can determine the unhealthy event

I read a paper regarding air quality. The author mentioned that "The PM10 pollutant also shows the highest of kurtosis value, which indicates that it appears most frequently in unhealthy pollution events." So I am confused about how to kurtosis…
Maryam
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Compositional analysis vs. Manly selection ratios

I am comparing habitat availability vs. use by a bird species using the R compana() function (package adehabitat) which uses Aebischer et al. (1993) method. It is a 3rd order habitat selection analysis, so the availability of habitats is different…
Maria
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Change Point Analysis for Environmental Data

Does anyone know of somewhere with resources on using change point analysis for determining environmental threshold values? Let me emphasize that this is NOT time series data. Change point analysis is often used in ecology to determine a point along…
WaterGeek
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What is the best correlation test to use when you want to compare two variables in a spatiotemporal context?

I have 9 sampling sites. I did the sampling in May, July, and September in the sediments and the water. So, I have 27 samples. I want to know if there is a linear correlation between total nitrogen concentration in the water and the sediments. What…
Simon Leclair
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How to choose the equally spaced values for temperature variable in R?

I am learning a distributed lag non-linear model. In that, I have to create a cross basis matrix first. For cross-basis, I need to specify the knots at equally spaced values of the temperature variable. This is the script I am using ktemp <-…
hasan arshad
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Modelling community as random effect based on community-level exposure?

I am conducting community/school research to exploring the health impact of environmental exposures (e.g., air pollution). The exposure is predicted based on the address of the community/school centroid using spatio-temporal model. Therefore, there…
Bender
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How to analyse temporal variation in R---vigilance of birds

I am currently doing a project for my Bachelor degree, for which I study vigilance in birds. Obviously, I have to analyse the data statistically. However, I do not know where to begin since I do not know which test to chose. I am interested in how…
Kalia
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finding the correlation between population density in a city and the city's PM 25 value

I am a high school student doing a report for my environmental science course, IB diploma. My question is about how to find the correlation between two data sets. My question of interest is whether a city's population density affects the city's air…
Lynn
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Preparing data for cross-correlation time series

I have several data sets with air quality measurements for 20 locations. The measurements were done per second over a period of two weeks, 5 locations per period (because there were only 5 instruments). The data looks stationary when plotted (see…
Qeshet
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How to develop the EKC regression model?

I want to use the environmental Kuznets curve (EKC) to check the relationship between increase economic growth and environmental degradation, but I am faced with a challenge on how and where to build this model. Can I develop an EKC model in Eviews…
Lionel Mbanda
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