the main objective in sampling is to select a sample from a population in order to estimate some unknown population parameter, usually a total or a mean of some interesting variable. a simple way to take a sample of size n is to let all the possible samples have the same probability of being selected. this is called simple random sampling and then all units have the same probability of being ch...

in fact, this study focused on the following questions: 1. is there any difference between the effect of functional/notional approach and the structural approaches to language teaching on the proficiency test of efl learners? 2. can a rather innovative language test referred to as "functional test" ge devised so so to measure the proficiency test of efl learners, and thus be as much reliable an...

abstract english language learning in iran has become significant in recent years, and english has been included in the curriculum of iranian schools and universities, and considerable attention has been paid to this language in our society. nevertheless, teaching and learning english in iranian schools has not been able to satisfy the specified goals, so different efl institutes have been est...

there are two major theories of measurement in psychometrics: classical test theory (ctt) and item-response theory (irt). despite its widespread and long use, ctt has a number of shortcomings, which make it problematic to be used for practical and theoretical purposes. irt tries to solve these shortcomings, and provide better and more dependable answers. one of the applications of irt is the as...

the rise and stublishment of safavid dynasty was depend on triangle of tasavof, tashayo and royalty, kings legitimized their power upon these. therefore for the understanding the functions of that period we must explore the role of this elements. although application and emphsise upon dignities such as; complete mentor (morshede kamel), deputy of absent imam (nayebe imame ghayeb), and god’s sha...

abstract in a protocol analysis of second language writing from 20 adult english as a foreign language (efl) iranian students, this research observed how language-switching (l-s), i.e., first language use in l2 writing, was affected by l2 proficiency. switching interactively between first (l1) and second (l2) languages has been recognized as one of the salient characteristics of l2 writing....

teachers’ beliefs greatly influence their performance in the classroom, their choice of instructional strategies, their way of controlling the class, their dealing with the students, and their general goals and objectives. one of these beliefs is teachers’ sense of efficacy which is viewed as an important construct and has shown to be positively correlated with students’ achievement (ross, 1992...

‏‎the main purpose of this research was to:1.develop a coking model for thermal cracking of naphtha.2.study coke inhibition methods using different coke inhibitors.developing a coking model in naphtha cracking reactors requires a suitable model of the thermal cracking reactor based on a reliable kinetic model.to obtain reliable results all these models shall be solved simultaneously.for this pu...

nowadays, air pollution is a global problem that has had significant growth by technology development, population growth andindustrial development. industrial development brought natural resources deterioration, more manufacturing products, and more environmental pollutants. if pollutant won’t be controlled, human-being and wildlife will face the critical risks. significant release and critical...

reinsurance is widely recognized as an important instrument in the capital management of an insurance company as well as its risk management tool. this thesis is intended to determine premium rates for different types of reinsurance policies. also, given the fact that the reinsurance coverage of every company depends upon its reserves, so different types of reserves and the method of their calc...