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...

all analytical methods are generally based on the measurement of a parameter or parameters which are somehow related to the concentration of the species.an ideal analytical method is one in which the concentration of a species can be measured to a high degree precision and accuracy and with a high sensitivity. unfortunately finding such a method is very difficult or sometimes even impossible.in...

abstract the following study, in the first place, attempted to examine the effect of less experienced teachers participation in experienced teachers classes on their own skills and teaching methodology, in the second place, attempted to find out the role of teachers training in students achievements. for this purpose, 21 efl teachers were selected according to available sampling in kish l...

the research questions were as follows: 1. is there any relationship between the students concious awareness of the form and implications of the conjuncations and their improvement in using appropriate conjunctions? 2. does students knowledge of the from and the implications of the conjunctions help them to produce more coherent writings. 3. does a comparison between english conjunctions and th...

we have devided the thesis in to five chapters. the first recollects facts from purely algebraic theory of jordan algebras and also basic properties of jb and jb* - algebras which are needed in the sequel. in the second chapter we extend to jb* - algebras, a classical result due to cleveland [8]. this result shows shows the weakness of jb* - norm topology on a jb* - algebera. in chapter three, ...

this study was intended to analyze the listening tapescripts of the elementary and pre-intermediate levels of total english textbooks from the pragmatic dimension of language functions and speech acts in order to see whether the listening tasks are pragmatically informative or not. for this purpose, 8 conversations from the two books were selected randomly, and then, the two pragmatic models of...

the history of plant’s used for mankind is as old as the start of humankind. initially, people used plants for their nutritional proposes but after the discovery of medicinal properties, this natural ?ora became a useful source of disease cure and health improvement across various human communities. berberis vulgaris is one of the medicinal plants used in iranian traditional medicine. berberis ...

abstract poor reading comprehension can result in failure in using references, benefiting from professional gatherings and resources, keeping up with the growing body of knowledge in the virtual world of the internet, and failing to achieve in efl programs. the purpose of the present quasi-experimental study was to explore the effects of background knowledge and previewing narrative and expos...

with the introduction of communicative language teaching, a large number of studies have concerned with students’ oral participation in language classrooms. although the importance of classroom participation is evident, some language learners are unwilling to engage in oral activities. this passivity and unwillingness to participate in language classroom discussions is known as “reticence”. rev...

the present research study attempted to find out the extent to which two pre-task activities of “glossary of unknown vocabulary items” and “content related support” assisted efl language learners with their performance on listening comprehension questions across two different proficiency levels (low and high). data for this study were obtained from a total of 120 language learners, female and m...