The Comparison of Two Methods of Maximum Likelihood (ML) and Diagonally Weighted Least Squares (DWLS) in Testing Construct Validity of Achievement Goals

ABSTRACT: The present essay was intended to compare between two methods of estimation, namely, Maximum Likelihood (ML) and Diagonally Weighted Least Squares (DWLS) in determination of construct validity of achievement goals. The statistical population of this investigation includes all high school third grade students in the fields of empirical sciences and math-physics from Isfahan City during academic year 2005-6, that they were totally 7278. 400 students were chosen by means of stratified sampling technique with proportional assignment. To measure achievement goals, two subscales of mastery goals and performance goals were used that have been exclusively prepared to utilize in the field of mathematics by Middleton and Midgley. The Cronbach alpha coefficients for variables of mastery goals were obtained as 0.76 and 0.82 respectively. The results showed that if the observed variables are ordinal and their categories are lesser than 5, then it is important to select DWLS method as the best choice for estimation before estimating parameters and review of data distribution with respect to type of data. If researcher does not checkup assumptions and adapts default estimation method (ML) so the results may be biased and this may lead to making the erroneous decisions

The current economics of fisheries (fishery and aquaculture) in Guilan, Mazandaran and Golestan provinces

Regarding the natural potential and socio-economic advantages of aquaculture development, extension of aquaculture has been raised as one of the priorities of the second to fifth national programs of the Islamic Republic of Ira in the fisheries sector in the past ten years. Proliferation and aquaculture development also plays an important role in increasing employment, exportation, and rural development in rural areas. Although the physical capacities of aquaculture development may be clear, it is necessary to analyze the profitability of farmers and fish market as well. In recent years, reproduction and breeding of new species, in order to increase the income of farmers, have been put on the agenda of the Fisheries Research Institute. In order to increase the maximum utilization of production capacity and increase the warm water pond valume per unit area of land, three species of Indian carp has been imported. The main problems of aquaculture economical research include inadequate information and lack of the collaboration between different experts and aquaculture farmers. The objective of the research was to survey of economical aspects for culturing the imported Indian carp. The fingerlings of the imported species were transferred to the target centers, Southern aquaculture Research institute and Inland waters Aquaculture Research institute. The experiment was carried out as three treatments in triplicates for 9 months. To determine the cost of production and the share of the cost of production factors for farmed fish carp, including the cost of labor, cost of fingerlings, feed and fertilizer costs, maintenance costs, energy costs, depreciation of structures, equipment and buildings for administrative and other costs; past experiences, information and other resources and external experiences questionnaire was employed