49
Limitations:
In spite of all the advantages mentioned above, this design suffers from the following limitations:
- The use of this design seriously restricts the external validity of the experiment. The experiment can partially overcome this limitation by replicating the experiment with different groups.
variable measures for the two groups are then compared (post-test), to determine the effect of independent or treatment variable x. If the experimental group performs better on the post-test (T ) the experimenters more confident that the independent variable is more responsible for the change in the dependent variable.
Illustration:
Suppose a teacher wants to evaluate the effectiveness of a new method teaching in teaching English to fifth grade students. He will frame two equivalent groups of 20 each from the same class of 40 students. One group will be taught by the new method and the other one by the conventional method. At the end of the experiment, an achievement test in English is administered to both the groups and a comparison is made of the achievement of students of the two groups. The means of the post-test T will be computed. An appropriate statistical test will be applied to ascertain whether the observed difference is statistically significant.
Paradigm for design 2: Two groups static design:
Group
Independent variable
Post-test
Experimental
Teaching through new method
T
Control
Teaching through conventional method
T
46
Limitations:
Since neither randomization nor matching is used to assign subjects to the experimental and control groups, the experimenter can not assume that the groups are equivalent with respect to relevant extraneous variables before they are exposed to the experimental treatment. This design, therefore, is also considered to be lacking in the necessary control. Any differences between the post-test measure T of experimental and control groups may come about through the biased selection or inclusion of the subjects forming the groups, or they may differ on certain relevant variables without the effect of the experimental variable. Moreover, experimental mortality may also produce difference in the groups due to differential dropout of subjects from the groups. Therefore, the two groups once equivalent may differ later because of selective dropout of subjects.
Design 3: Two groups, randomized subjects, post-test only design:
This design is one of the simplest and powerful experimental designs. The available subjects are assigned to two groups through randomization which controls for all possible relevant extraneous variables. No pre-test is used and the random assignment of subjects assures that any initial differences between the groups are attributable only to chance. The two random samples from designed population are obtained in two ways: (1) The subjects may be drawn individually at random and assigned alternatively to the groups: or (2) two different random samples may be selected first and the groups are assigned randomly to the experimental or control condition by the flip of a coin. Only the experimental group is exposed to the experimental treatment. At the end of the experiment, subjects of both the groups are measured on the dependent variable T2. The means of the two groups are compared with the help of appropriate statistical test of significance.
47
Illustration:
Suppose an experimenter wants to ascertain whether a new teaching method will increase reading speed of secondary school students. He prepares a list of all the secondary schools of a particular city and assigns numbers to all the secondary schools students. With the help of random number table he may draw a desired sample of 100 students. Then two random samples of 50 subjects each may be selected from the selected sample in two way: the researcher may select subjects individually at random and assign them alternately to the groups, o he may first draw two random samples and then assign groups to the experimental or control condition by tossing a coin.
After assigning the subject to two groups, the experimental group is taught through the new method and the control group through the conventional method, for a period of time. In all other respects, the researcher will treat the groups alike. After the desired period of time, the subjects of both the groups will be administered a reading test. The mean scores of the two groups are compared to determine the effectiveness of new teaching method by using an appropriate statistical test. If the obtained means of the groups are significantly different, the experimenter can be reasonably confident that the use of new teaching method was responsible for the observed difference.
48
PARADIGM FOR THE DESIGN 3: Two groups, randomized subjects
Post Test Only Design
Randomly assigned group
Independent variable
Post-test
Experimental
Teaching through new method
T
Control
Teaching through conventional method
T
Advantages:
- The main advantage of this design is randomization, which assures statistical equivalent of the groups prior to the introduction of the experimental treatment.
- Since no pre-test is used, this design controls for the main effects of history. Maturation and pre-testing. Moreover, there can be no interaction effect of pre-test and independent or experimental variable. Hence, this design is especially recommended for the experiments in which pre-test sensitization is likely to occur.
- This design is useful in the experimental studies, especially at kindergartens or primary stages, in which a pre-test is either not available or not appropriate.
- If necessary, this design can be extended to include more than two groups.
- There are some situations in which it is not possible for the experimenter to select subjects at random from the population of interest.
TEST
- Describe the nature of experimental research.
- List and describe the essential characteristics of experimental research.
- Compare the experimental method with the historical method of research.
- Compare the experimental method with the descriptive method of research.
- Define the term control.
- List and describe the purposes of control in an experiment.
51
THE HISTORICAL METHOD
NATURE:
Historical research attempts to establish fact so as to arrive at concussions concerning past events. This is usually accompanied by an interpretation of these events and of their relevance to present circumstances and what might happen in that future. The main purpose of historical research, therefore, is to arrive at an accurate account of the past so as to gain a clearer perspective of the present. This knowledge enables us at least partially to predict and control our future existence.
Historical research, as any other type of research, includes the delimitation of a problem, formulation hypotheses or tentative generalizations, gathering and analyzing data, and arriving at conclusions or generalizations based upon deductive-inductive reasoning.
VALUE:
Historical research has great value in the field of educational research because it is necessary to know and understand educational achievements and trends of the past in order to gain perspective on present and future direction.
TYPES:
Bibliographic research.
Studying the history of ideas.
Studying the history of institutions and organizations.
51
Bibliographic Research:
Bibliographic research aims at determining and presenting truthfully the important facts about the life, character, and achievements of important educators.
Studying the History Of Ideas
Studying the history of ideas involves the tracing of major philosophical or scientific thoughts from their origins through their different stages of development. It also aims at tracing of changes in popular thoughts and attitudes over a given period of time. The evolution of current concepts.
Studying the History of Institutions and Organizations:
Studying the history of some prominent schools, universities and other educational institutions also provide numerous problems for significant historical research. When studying such history, the same general method applies as for the study of an educator’s life.
Steps in historical research:
The steps involved in undertaking a historical research are not different from other forms of research, but the nature of the subject matter present a researcher some peculiar problem and require him to apply some special standards and techniques. In general, historical research involves the following steps :
Selection of the problem
Formulation of hypotheses
Collection of data
Criticism of data
Interpretation and reporting of finding
52
Selection of the problem
A researcher may select a problem pertaining to the history of individuals, institutions, organizations, law, curriculum, administration, textbooks, teacher education, equipment, important concepts and thoughts that have influenced education during a specific period of time in a given culture or sub- culture determined by religion, caste, sex, age or work. He may delimit his study to an era of events in a local, regional, or national setting, or he may study the trend of events in different eras, different societies, or different cultures, The historian may discover new knowledge, the meaning of which, when interpreted will provide answers about past events. Sometimes he may doubt an old interpretation of existing data and then attempt to provide a more satisfactory explanation of past events.
Formulation of hypotheses:
The hypotheses that the researcher constructs for historical research are useful in explaining events, conditions or phenomena of the historical period in question. Sometimes it is argued that in such type of studies a researcher is merely interested in concrete events in their singularity, he has merely to check the validity and authenticity of facts about past events and arrange them in a chronological sequence. Therefore, the researcher may not formulate any hypotheses in such investigation
النتائج (
العربية) 1:
[نسخ]نسخ!
49القيود:وعلى الرغم من كل المزايا المذكورة أعلاه، يعاني هذا التصميم من القيود التالية:-استخدام هذا التصميم جدية يقيد صلاحية الخارجية للتجربة. التجربة يمكن التغلب على هذا القيد جزئيا بتكرار التجربة مع مختلف المجموعات.تدابير لهاتين المجموعتين متغير ثم مقارنة (بعد الفحص)، لتحديد أثر x المتغير المستقل أو المعالجة. إذا كان أداء المجموعة التجريبية أفضل في مرحلة ما بعد الاختبار (T) المجربون أكثر ثقة بأن المتغير المستقل أكثر مسؤولية عن التغير في المتغير التابع.المثال التوضيحي:افترض أن معلم يريد أن تقييم فعالية أسلوب جديد في التدريس في تدريس اللغة الإنكليزية لطلاب الصف الخامس. أنه سيكون الإطار فريقين ما يعادل 20 كل من نفس الفئة من 40 طالبا. وسوف تدرس مجموعة واحدة بأسلوب جديد، والآخر بالطريقة التقليدية. في نهاية التجربة، تدار على اختبار إنجاز باللغة الإنجليزية لكلا الفريقين وهو إجراء مقارنة لتحقيق الطلاب للفريقين. وسوف يحسب وسائل تي بعد انتهاء الاختبار. سيتم تطبيق اختبار إحصائية مناسبة للتحقق من ما إذا كان الاختلاف الملحوظ يعتد به إحصائيا.نموذج لتصميم 2: اثنين مجموعات تصميم ثابت:المجموعةالمتغير المستقلبعد انتهاء الاختبارالتجريبيةالتدريس من خلال الأسلوب الجديدTعنصر التحكمTeaching through conventional methodT46Limitations:Since neither randomization nor matching is used to assign subjects to the experimental and control groups, the experimenter can not assume that the groups are equivalent with respect to relevant extraneous variables before they are exposed to the experimental treatment. This design, therefore, is also considered to be lacking in the necessary control. Any differences between the post-test measure T of experimental and control groups may come about through the biased selection or inclusion of the subjects forming the groups, or they may differ on certain relevant variables without the effect of the experimental variable. Moreover, experimental mortality may also produce difference in the groups due to differential dropout of subjects from the groups. Therefore, the two groups once equivalent may differ later because of selective dropout of subjects.Design 3: Two groups, randomized subjects, post-test only design:This design is one of the simplest and powerful experimental designs. The available subjects are assigned to two groups through randomization which controls for all possible relevant extraneous variables. No pre-test is used and the random assignment of subjects assures that any initial differences between the groups are attributable only to chance. The two random samples from designed population are obtained in two ways: (1) The subjects may be drawn individually at random and assigned alternatively to the groups: or (2) two different random samples may be selected first and the groups are assigned randomly to the experimental or control condition by the flip of a coin. Only the experimental group is exposed to the experimental treatment. At the end of the experiment, subjects of both the groups are measured on the dependent variable T2. The means of the two groups are compared with the help of appropriate statistical test of significance.47Illustration:Suppose an experimenter wants to ascertain whether a new teaching method will increase reading speed of secondary school students. He prepares a list of all the secondary schools of a particular city and assigns numbers to all the secondary schools students. With the help of random number table he may draw a desired sample of 100 students. Then two random samples of 50 subjects each may be selected from the selected sample in two way: the researcher may select subjects individually at random and assign them alternately to the groups, o he may first draw two random samples and then assign groups to the experimental or control condition by tossing a coin.After assigning the subject to two groups, the experimental group is taught through the new method and the control group through the conventional method, for a period of time. In all other respects, the researcher will treat the groups alike. After the desired period of time, the subjects of both the groups will be administered a reading test. The mean scores of the two groups are compared to determine the effectiveness of new teaching method by using an appropriate statistical test. If the obtained means of the groups are significantly different, the experimenter can be reasonably confident that the use of new teaching method was responsible for the observed difference.48PARADIGM FOR THE DESIGN 3: Two groups, randomized subjectsPost Test Only DesignRandomly assigned groupIndependent variablePost-testExperimentalTeaching through new methodTControlTeaching through conventional methodTAdvantages:- The main advantage of this design is randomization, which assures statistical equivalent of the groups prior to the introduction of the experimental treatment.- Since no pre-test is used, this design controls for the main effects of history. Maturation and pre-testing. Moreover, there can be no interaction effect of pre-test and independent or experimental variable. Hence, this design is especially recommended for the experiments in which pre-test sensitization is likely to occur.- This design is useful in the experimental studies, especially at kindergartens or primary stages, in which a pre-test is either not available or not appropriate.- If necessary, this design can be extended to include more than two groups.- There are some situations in which it is not possible for the experimenter to select subjects at random from the population of interest.TEST- Describe the nature of experimental research.- List and describe the essential characteristics of experimental research.- Compare the experimental method with the historical method of research.- Compare the experimental method with the descriptive method of research.- Define the term control.- List and describe the purposes of control in an experiment.51THE HISTORICAL METHODNATURE:Historical research attempts to establish fact so as to arrive at concussions concerning past events. This is usually accompanied by an interpretation of these events and of their relevance to present circumstances and what might happen in that future. The main purpose of historical research, therefore, is to arrive at an accurate account of the past so as to gain a clearer perspective of the present. This knowledge enables us at least partially to predict and control our future existence.Historical research, as any other type of research, includes the delimitation of a problem, formulation hypotheses or tentative generalizations, gathering and analyzing data, and arriving at conclusions or generalizations based upon deductive-inductive reasoning.VALUE:Historical research has great value in the field of educational research because it is necessary to know and understand educational achievements and trends of the past in order to gain perspective on present and future direction.TYPES:Bibliographic research.Studying the history of ideas.Studying the history of institutions and organizations.51Bibliographic Research:Bibliographic research aims at determining and presenting truthfully the important facts about the life, character, and achievements of important educators.Studying the History Of IdeasStudying the history of ideas involves the tracing of major philosophical or scientific thoughts from their origins through their different stages of development. It also aims at tracing of changes in popular thoughts and attitudes over a given period of time. The evolution of current concepts.Studying the History of Institutions and Organizations:Studying the history of some prominent schools, universities and other educational institutions also provide numerous problems for significant historical research. When studying such history, the same general method applies as for the study of an educator’s life.Steps in historical research:The steps involved in undertaking a historical research are not different from other forms of research, but the nature of the subject matter present a researcher some peculiar problem and require him to apply some special standards and techniques. In general, historical research involves the following steps :Selection of the problemFormulation of hypothesesCollection of dataCriticism of dataInterpretation and reporting of finding52Selection of the problemA researcher may select a problem pertaining to the history of individuals, institutions, organizations, law, curriculum, administration, textbooks, teacher education, equipment, important concepts and thoughts that have influenced education during a specific period of time in a given culture or sub- culture determined by religion, caste, sex, age or work. He may delimit his study to an era of events in a local, regional, or national setting, or he may study the trend of events in different eras, different societies, or different cultures, The historian may discover new knowledge, the meaning of which, when interpreted will provide answers about past events. Sometimes he may doubt an old interpretation of existing data and then attempt to provide a more satisfactory explanation of past events.Formulation of hypotheses:The hypotheses that the researcher constructs for historical research are useful in explaining events, conditions or phenomena of the historical period in question. Sometimes it is argued that in such type of studies a researcher is merely interested in concrete events in their singularity, he has merely to check the validity and authenticity of facts about past events and arrange them in a chronological sequence. Therefore, the researcher may not formulate any hypotheses in such investigation
يجري ترجمتها، يرجى الانتظار ..
