Econometrics is the application of statistical methods to economic data in order to give empirical content to economic relationships. More it is "the quantitative analysis of actual economic phenomena based on the concurrent development of theory and observation, related by appropriate methods of inference". An introductory economics textbook describes econometrics as allowing economists "to sift through mountains of data to extract simple relationships"; the first known use of the term "econometrics" was by Polish economist Paweł Ciompa in 1910. Jan Tinbergen is considered by many to be one of the founding fathers of econometrics. Ragnar Frisch is credited with coining the term in the sense. A basic tool for econometrics is the multiple linear regression model. Econometric theory uses statistical theory and mathematical statistics to evaluate and develop econometric methods. Econometricians try to find estimators that have desirable statistical properties including unbiasedness and consistency.
Applied econometrics uses theoretical econometrics and real-world data for assessing economic theories, developing econometric models, analysing economic history, forecasting. A basic tool for econometrics is the multiple linear regression model. In modern econometrics, other statistical tools are used, but linear regression is still the most used starting point for an analysis. Estimating a linear regression on two variables can be visualised as fitting a line through data points representing paired values of the independent and dependent variables. For example, consider Okun's law, which relates GDP growth to the unemployment rate; this relationship is represented in a linear regression where the change in unemployment rate is a function of an intercept, a given value of GDP growth multiplied by a slope coefficient β 1 and an error term, ε: Δ Unemployment = β 0 + β 1 Growth + ε. The unknown parameters β β 1 can be estimated. Here β 1 is estimated to be −1.77 and β 0 is estimated to be 0.83.
This means that if GDP growth increased by one percentage point, the unemployment rate would be predicted to drop by 1.77 points. The model could be tested for statistical significance as to whether an increase in growth is associated with a decrease in the unemployment, as hypothesized. If the estimate of β 1 were not different from 0, the test would fail to find evidence that changes in the growth rate and unemployment rate were related; the variance in a prediction of the dependent variable as a function of the independent variable is given in polynomial least squares. Econometric theory uses statistical theory and mathematical statistics to evaluate and develop econometric methods. Econometricians try to find estimators that have desirable statistical properties including unbiasedness and consistency. An estimator is unbiased. Ordinary least squares is used for estimation since it provides the BLUE or "best linear unbiased estimator" given the Gauss-Markov assumptions; when these assumptions are violated or other statistical properties are desired, other estimation techniques such as maximum likelihood estimation, generalized method of moments, or generalized least squares are used.
Estimators that incorporate prior beliefs are advocated by those who favour Bayesian statistics over traditional, classical or "frequentist" approaches. Applied econometrics uses theoretical econometrics and real-world data for assessing economic theories, developing econometric models, analysing economic history, forecasting. Econometrics may use standard statistical models to study economic questions, but most they are with observational data, rather than in controlled experiments. In this, the design of observational studies in econometrics is similar to the design of studies in other observational disciplines, such as astronomy, epidemiology and political science. Analysis of data from an observational study is guided by the study protocol, although exploratory data analysis may be useful for generating new hypotheses. Economics analyses systems of equations and inequalities, such as supply and demand hypothesized to be in equilibrium; the field of econometrics has developed methods for identification and estimation of simultaneous-equation models.
These methods are analogous to methods used in other areas of science, such as the field of system identification in systems analysis and control theory. Such methods may allow researchers to estimate models and investigate their empirical consequences, without directly manipulating the system. One of the fundamental statistical methods used by econometricians is regression analysis. Regression methods are important i
Akodon is a genus consisting of South American grass mice. They occur south of the Amazon Basin and along the Andes north to Venezuela, but are absent from much of the basin itself, the far south of the continent, the lowlands west of the Andes. Akodon is one of the most species-rich genera of Neotropical rodents. Species of Akodon are known to inhabit a variety of habitats from tropical and tropical moist forests to altiplano and desert. Fossils are known from the late Pliocene onwards. Akodon is the largest genus in the tribe Akodontini. Three of its synonyms—Chalcomys and Microxus—have sometimes been regarded as distinct genera. Neomicroxus was separated in 2013. Associated with Akodon, the genera Abrothrix, Necromys and Thaptomys are recognized as distinct; some species of the tribe Abrotrichini are called akodons. The genus contains the following species: Akodon aerosus Akodon affinis Akodon albiventer Akodon azarae Akodon boliviensis Akodon budini Akodon caenosus Akodon cursor Akodon dayi Akodon dolores Akodon fumeus Akodon glaucinus Akodon iniscatus Akodon juninensis Akodon kofordi Akodon lindberghi Akodon lutescens Akodon mimus Akodon molinae Akodon mollis Akodon montensis Akodon mystax Akodon neocenus Akodon orophilus Akodon paranaensis Akodon pervalens Akodon philipmyersi Akodon polopi Akodon reigi Akodon sanctipaulensis Akodon serrensis Akodon siberiae Akodon simulator Akodon spegazzinii Akodon subfuscus Akodon surdus Akodon sylvanus Akodon tartareus Akodon toba Akodon torques Akodon varius Braun, J.
K. Coyner, B. S. Mares, M. A. and Van Den Bussche, R. A. 2008. Phylogenetic relationships of South American grass mice of the Akodon varius group in South America. Journal of Mammalogy 89:768-777. Braun, J. K. M. A. Mares, B. S. Coyner, R. A. Van Den Bussche. 2010. New species of Akodon from central Argentina. Journal of Mammalogy, 91:387–400. D'Elía, G. Jayat, J. P. Ortiz, P. E. Salazar-Bravo, J. and Pardiñas, U. F. J. 2011. Akodon polopi Jayat et al. 2010 is a senior subjective synonym of Akodon viridescens al.. 2010. Zootaxa 2744:62–64. Jayat, J. P. Ortiz, P. E. Salazar-Bravo, J. Pardiñas, U. F. J. and D'Elía, G. 2010. The Akodon boliviensis species group in Argentina: species limits and distribution, with the description of a new entity. Zootaxa 2409:1–61. Musser, G. G. and Carleton, M. D. 2005. Superfamily Muroidea. Pp. 894–1531 in Wilson, D. E. and Reeder, D. M.. Mammal Species of the World: a taxonomic and geographic reference. 3rd ed. Baltimore: The Johns Hopkins University Press, 2 vols. 2142 pp. ISBN 978-0-8018-8221-0 Pardiñas, U.
F. J. D'Elía, G. Cirignoli, S. and Suarez, P. 2005. A new species of Akodon from the Northern Campos grasslands of Argentina. Journal of Mammalogy 86:462–474. Pardiñas, U. F. J. Teta, P. D'Elía, G. and Diaz, G. B. 2011. Taxonomic status of Akodon oenos, an obscure species from West Central Argentina. Zootaxa 2749:47–61
Iskashitaa Refugee Network is a grass roots organization based in Tucson, Arizona that partners with volunteers and local organizations to provide various supplemental services to refugees to complement those offered by resettlement agencies. The organization was founded by Dr. Barbara Eiswerth, who holds a Ph. D. in Arid Lands Resource Management, is directed by Eiswerth. Iskashitaa has a number of programs designed to empower refugees and unite them with staff and volunteers from the community. A primary component of these programs is gleaning, or harvesting unwanted produce from property owners and commercial farmers. Over Iskashitaa's ten years of existence, gleaning efforts have grown from harvesting a few thousand pounds of fruit each year to over 100,000 pounds annually of fruit and vegetables: a cumulative one million servings of local produce. Iskashitaa means "working cooperatively together" in the language of the Somali Bantu people, called Maay Maay; the spelling of Iskashitaa was chosen by Eiswerth, as there was no written representation of the Maay Maay language at the time of Iskashitaa's inception.
In its early years, the name of the organization was spelled with an asterisk, as Iskash*taa. Iskashitaa worked with Somali Bantus, but has expanded to work with refugee populations from around the world; these refugees and asylum seekers arrive from Afghanistan, Burma, the Central African Republic, the Democratic Republic of the Congo, the Republic of the Congo, Equatorial Guinea, Ethiopia, Iraq, Russia, Somalia, South Sudan and Syria. Eiswerth worked as a researcher in Malawi villages, wrote her dissertation there. Upon her return to Tucson, she noticed rotting fruit that had fallen from trees and began the harvesting work for which Iskashitaa is known, her background in environmental science and land management combined with her experience in Africa inspired her to start the harvesting work for which Iskashitaa is known. "As an environmental scientist, the road to sustainability is using what we have right here," she says. "We can do the right thing, not let food go to waste." In 2002, Eiswerth launched a project through the Tucson Youth Work Enhancement program to educate local high school teens about food resources.
Together, they mapped 162 homes with 296 fruit-producing trees. Unwanted fruit harvested from these trees was distributed to local farmers' markets and soup kitchens. In 2003, Eiswerth recruited refugee students to participate in a project identifying locations of produce, going to waste in Tucson, as she had with the high school students; the refugee youth redistributed this food. After organizing two more youth mapping programs, Eiswerth received a grant from the United Way of America to begin harvesting with refugees. Since Iskashitaa has gathered about 400,000 pounds of produce, redistributed to thousands of Tucson residents experiencing food insecurity. Over the years, the organization has offered English and swimming lessons for refugees, cooking classes for the members of the community and craft circles, catalog sales of the goods Iskashitaa refugees make. Iskashitaa Refugee Network is an Arizona nonprofit. Iskashitaa is under the fiscal umbrella of St. Francis in the Foothills UMC. A federal is working to become an independent non-profit association.
Iskashitaa's funding comes from a combination of donations and earned income through sales. Iskashitaa Refugee Network is a local nonprofit whose mission is to assist refugees on their journeys to fulfilled lives in Tucson, using food-based programming as an entry point to community. Iskashitaa's primary objective is to "empower refugees by creating opportunities to better integrate with the larger Tucson community while gaining skills that serve them in America." The organization's programs utilize connections and English language practice to attain this objective. Iskashitaa has built a networking community among Tucson area refugee volunteers and agencies that cooperate to make this mission possible. Iskashitaa Harvesting Iskashitaa harvesters consist of an inter-generational group of refugees from Africa and the Middle East as well as local Tucsonan volunteers; this group harvests 100,000 pounds of fruits and vegetables each year from backyards and local farms. This produce is redistributed to refugee families from many countries, food shelves, other Tucson organizations that assist food insecure families, either for free or for a nominal price.
Iskashitaa Cooking and Food Preservation Refugees teach other Iskashitaa volunteers and staff about their own cultural dishes using food, harvested. These interactions intend to make refugees more comfortable in an American kitchen, introduce Tucson locals to different cultures. Volunteers and program staff teach refugees how to make preserved foods from their own families' traditions. Groups have prepared jams, preserves, Nepali spices, juices, to name a few. Food products are sold at local stores to sustain the organization's work. English as a Second Language Iskashitaa offers ESL Classes to refugees, designed to work with every individual, regardless of education levels or diverse backgrounds and languages; these classes focus on language acquisition and cultural exchange, work to develop relationships between teachers and students, as well as assist in the acculturation process by introducing material based on life in the United States. Students interact with Tucson locals through Iskashitaa's other programs to practice their new language skills.
College students from the University