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Research Approach Qualitative Quantitative Experimental Pre experiment
Ex Post Facto True Experiment Correlational Quasi Experiment Survey EDU 5900 AB RAHIM BAKAR
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Types of Research Purpose or end sought EXPLORE DESCRIBE EXPLAIN-
To become familiar with phenomena; to gain new insight; to formulate a more specific research problem or research hypothesis (use research questions or objectives To portray accurately the incidence, distribution, and characteristics of a group or situation (usually do not begin with specific hypothesis; use research questions or objectives To investigate relationships between variables (Begin with specific hypothesis) To test hypotheses of causal relationships between variables EXPLORE DESCRIBE EXPLAIN- PREDICT CONTROL Descriptive [PRE EXPERIEMNTAL] SURVEY RESEARCH CORR & EX POST TRUE EXP & QUASI EXP EDU 5900 AB RAHIM BAKAR
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Research Approach Qualitative Quantitative Experimental Pre experiment
Ex Post Facto True Experiment Correlational Quasi Experiment Survey EDU 5900 AB RAHIM BAKAR
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Experimental Research Designs have Two Purposes:
…to provide answers to research questions ...to control variance (differences) EDU 5900 AB RAHIM BAKAR
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In other words control variance.
The main function of the experimental research design is to control variance. Principle: maximize systematic variance, control extraneous systematic variance, and minimize error variance. MAX-MIN-CON In other words control variance. EDU 5900 AB RAHIM BAKAR
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Therefore the researcher attempts to:
maximize the variance of the variable(s) of the research hypothesis (i.e., maximize the difference in the dependent variable [outcome] caused by maximizing the differences in the independent variable [treatment]). control the variance of extraneous or "unwanted" variables that may have an effect on the experimental outcomes, but which he/she is not interested (limit factors other than the treatment (IV) that could be causing differences in the outcome (DV) . minimize the error or random variance (i.e., avoid unreliable measurement instruments which have high errors of measurement ). EDU 5900 AB RAHIM BAKAR
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Maximization of Experimental Variance
the variance due to the manipulated (i.e., treatment) or attribute (i.e., gender) variables (IV) research precept: design, plan and conduct research so that experimental conditions are as different as possible on the independent variable. EDU 5900 AB RAHIM BAKAR
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Maximization of Experimental Variance
the variance due to the manipulated (i.e., treatment) or attribute (i.e., gender) variables (IV) research precept: design, plan and conduct research so that experimental conditions are as different as possible on the independent variable. EDU 5900 AB RAHIM BAKAR
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Minimizing Error Variance has Two Principle Aspects:
reduction of errors of measurement through controlled conditions (i.e., standardize testing procedures) increase in the reliability of measures (i.e., revise test instruments or find more reliable ones) EDU 5900 AB RAHIM BAKAR
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Experimental Designs Three types of experimental research designs:
pre-experiment, true experimental and quasi-experimental. EDU 5900 AB RAHIM BAKAR
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These designs are generally used to determine cause and effect
These designs are generally used to determine cause and effect. They allow us to make inferences. According to David Hume, there are three criteria to be met to infer causality: Contiguity between the presumed cause and effect. In other words, the causal variable (independent) and the effect variable (dependent) must be associated. Temporal Precedence. In other words, the cause must precede effect. Constant conjunction. In other words, the cause is present whenever the effect is obtained. EDU 5900 AB RAHIM BAKAR
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All experiments involve treatment outcome units of assignment
comparison from which change can be inferred and attributed to the treatment. EDU 5900 AB RAHIM BAKAR
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Characteristics of True Experiments
Manipulation The experimenter does something to at least some of the subjects in the experiment. The introduction of that something is often referred to as the experimental treatment or experimental Intervention. This is also known as the independent variable. The researcher manipulates this independent variable by administering it to some subjects and withholding it from other subjects. In other words, the experimenter varies the independent variable and observes the effect that the manipulation has on the dependent variable of interest. EDU 5900 AB RAHIM BAKAR
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Control Control summarizes all of the major experimental activities. They are manipulation, use of comparison (control) groups, and randomization. Campbell and Stanley (1963) observed that obtaining scientific evidence requires at least one comparison. Control groups are used for this purpose. The term control group refers to the subjects that do not receive the experimental treatment and their performance on the dependent variable serves as a basis for evaluating the performance of the experimental group (the group who received the experimental treatment) on the same dependent variable. EDU 5900 AB RAHIM BAKAR
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Randomization The assignment of subjects to groups on a random basis. The term random essentially means that every subject has an equal chance of being assigned to any group. The intent is to equalize the groups however, there is no guarantee that the groups will be equal. The chance of obtaining unequal groups diminishes as the sample size increases. Researchers generally use a table of random numbers to facilitate the randomization EDU 5900 AB RAHIM BAKAR
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Strengths of the Experimental Design
Some researchers believe that this is the most powerful research design as it gives us cause and effect relationships. If we do this then we can expect that. This if-then relationship is important to those health care practitioners who want to predict and control. Therefore the strength lies in the fact that causal relationships can be inferred. This is not without controversy. Some scholars believe that the notion of causality among phenomenon is untenable. EDU 5900 AB RAHIM BAKAR
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Weakness of the Experimental Design
There are a number of variable of interest that are not amenable to manipulation. For instance we cannot randomly confer upon infants their weight at birth to observe the effect of birth weight on subsequent morbidity. Ethical considerations may prevent the manipulation of the independent variable. You would not inflict pain for the sake of an experiment. Artificial circumstances may affect the results. Laboratory designs take place in an artificial setting. Easier to control for external variables and is not as generalizable because it constrains the human experience. Field designs take place in the actual setting and may be better but there are more problems with controls. The Hawthorne Effect: effect of being in the study group may be sufficient to cause people to change their behaviors. This is the reason that double blind studies are conducted. In which neither subject nor those who administer the treatment knows which is the experimental or control group. EDU 5900 AB RAHIM BAKAR
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Pre-Experimental Designs 1. One-Shot Case Study X O
2. One-Group Pretest-Posttest Design O1 X O2 3. Static-Group Comparison or Intact- Group Comparison X O1 or X1 O1 O X2 O2 EDU 5900 AB RAHIM BAKAR
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New textbook pencapaian
One shot case study ( X O) satu kumpulan diberikan treatment atau didedahkan kepada suatu jenis treatment kemduain pengukuran dilakukan. Misalnya try to determine the effect of a new teksbook on pencapaian dalam peperiksaan X O New textbook pencapaian Tiada kawalan; no comparison (O1) yang ada hanyalah O2; no pretest score (O1) Jadi tak pasti samada O di sebabkan oleh X So, what causes O? Tak pasti lagi! EDU 5900 AB RAHIM BAKAR
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One-group pretest-posttest design O1 X O2
Still no control group. Tapi tahu ada perubahan atau tidak kerana ada maklumat awal mengenai pencapaian subject berkenaan (pretest score). Need to have a comparison group yang tak dapat treatmeNt yang sama. belum boleh buat andaian lagi bahawa perubahan disebabkan oleh X EDU 5900 AB RAHIM BAKAR
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History? Events that may occur between the two observations
What are the threats to internal validity posed by this design? Almost all!! Except selection & mortality. History? Events that may occur between the two observations Maturation > biological and psychological (grow older, tired, bored etc) Testing > Instrument decay > perubahan yang sengaja atu tidak sengaja (oberver/interviewer) EDU 5900 AB RAHIM BAKAR
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STATIC GROUP COMPARISON
X O1 inquiry Ujian X O2 lecture ujian Gunakan dua atau lebih kumpulan eksperimen Existing group or intact group (2 classrooms) No randomization of subjects to groups. Sebab tak boleh nak randomized. EDU 5900 AB RAHIM BAKAR
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Banyak digunakan dalam penyelidikan pendidikan
Berikan treatment yang berbeza (kaedah mengajar inquiry to group A dan lecture to group B) Administrative performance of principals with bachelor degree and principals with Masters degree. Any internal validity threats? Khususnya selection and mortality. What selection? No random assignment of subjects to groups. Differences of subject characteristics. EDU 5900 AB RAHIM BAKAR
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True experimental designs include:
-pre-test/post-test control group design -Solomon four-group design -post-test only control group design EDU 5900 AB RAHIM BAKAR
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Pretest-Posttest Control Group Design R O1 X O2 or R O1 X1 O2
R O3 O4 R O3 X2 O4 which can easily be extended to R O1 X1 O2 R O3 X2 O4 R O5 X3 O6 R O7 X4 O8 EDU 5900 AB RAHIM BAKAR
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The pre-test-post-test experimental design is more complex
The pre-test-post-test experimental design is more complex. It is called pre-test-post-test because there are two points of measurement, one before the experimental treatment and one after the experimental treatment. Example: Suppose we wanted to examine the effect on the heart rate of being restrained. The design would involve imposing a posey belt on the experimental group and no posey belt on the control group. The dependent variable which is the heart rate would be measured at two points in time. Before the posey belt and after the posey belt. This allows us to examine if heart rate changes were produced as a result of being restrained. EDU 5900 AB RAHIM BAKAR
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Kawal kesemua threats to internal validity
Kenapa ada prestest? Means of checking if both groups are similar & assess if changes occur due to treatment not because of existing factors Dapatkan perbezaan skor ( O2 - O1) dan (O4 - O3). Jalankan ujian t atau anova (?) untuk uji hipotesis yang mengatakan treatment tidak ada kesan ke atas pencapaian. EDU 5900 AB RAHIM BAKAR
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Randomize Posttest-Only Control Group Design
R X O1 or R X1 O1 R O R X2 O2 which can easily be extended to R X1 O1 R X2 O2 R X3 O3 R X4 O4 EDU 5900 AB RAHIM BAKAR
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The post-test only experimental design is a simple design
The post-test only experimental design is a simple design. It is called post-test only because the data is collected after the experimental treatment is complete. Example: Hypothesis is that the color of a pediatric nurses uniform affects the degree to which children display positive and negative affective behavior (laughing, crying). The causative or independent variable is the uniform color and the effect variable or dependent variable is the child’s behavior. The independent variable is manipulated by assigning some nurses white uniforms and some nurses colored uniforms. Thus, in this study we could compare the affective behaviors of children cared for by nurses in white uniforms and those cared for nurses in colored uniforms. EDU 5900 AB RAHIM BAKAR
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Subject di tempatkan dalam kumpulan secara random
Control for selection, maturation, statistical regression, testing. May not control mortality- drop out> why drop out? report berapa bilangan subject yang drop out Drop out cuase dissimilarity of the groups Instrumentation, history may still be the threats Example of a study using this design? Perhaps of all design to use if we have 40 subjects in each group (Frankael & Wallen, 1990) EDU 5900 AB RAHIM BAKAR
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Solomon Three-Group Design
Three groups are involved Overcoming the difficulty in Pretest-Posttest Control Group Design [effect pf pretesting and treatment] A second control group [C2) is not pretested but exposed to treatment Compare the Y2 of the three groups to see if treatment really made the difference You can check of the interaction effect between pretest and treatment….. EDU 5900 AB RAHIM BAKAR
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SOLOMON THREE GROUP DESIGN
Pretest Treatment Posttest (R) E Y1 X Y2 C1 _ C2 EDU 5900 AB RAHIM BAKAR
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Solomon Four-Group Design R O1 X O2 or R O1 X1 O2 R O3 O4 R O3 X2 O4
R X O R X1 O5 R O R X2 O6 Rekabentuk ini merupakan modifikasi posttest only control group or pretest-posttest control group (Frankel & Wallen, 1990) yang membolehkankan kita melihat kesan pembolehubah tambahan EDU 5900 AB RAHIM BAKAR
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EDU 5900 AB RAHIM BAKAR
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The Solomon four-group design is a version of the pre-test-post-test design.
It adds two addition groups. The purpose of adding the two groups is to separate the effects of the pre-test and to segregate it from the intervention.. In other words, a pre-test may be a sensitizing treatment that may affect the results of an actual treatment. 1 is an experimental groups without the pretest 1 is the control group without the pre test Example: If our intervention was a workshop to improve nurses attitudes toward alcoholic patients, the pre-test may sensitize the nurses and affect their attitudes at that point and obscure the analysis of the workshop’s effect. EDU 5900 AB RAHIM BAKAR
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Usaha untuk menghapuskan kemungkinan kesan pretesting
Random assignment of subjects to four groups. Dua mendapat pretest dan dua lagi tidak. Kesemuanya akan diposttest Better control for IV threat but require larger sample and a lot of hard work Have to conduct two experiments simultaneously EDU 5900 AB RAHIM BAKAR
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Strength of Solomon Four Group Design
Incorporate strengths of design Solomon Three Group Design and Randomized Pre and Posttest Designs, Randomized Posttest Only Control Group Design Can make several comparison to determine the effect of the treatment EDU 5900 AB RAHIM BAKAR
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Group Pretest Treatment Posttest (R) E Y0 X Y1 C1 Y01 _ Y2 C2 Y3 C3 Y4
EDU 5900 AB RAHIM BAKAR
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Factorial designs Two or more variables are manipulated simultaneously in order to study the independent effect of each variable on the dependent variable as well as the effect caused by interaction of several independent variables We can have the design whereby we manipulate only one independent variables or more than one independent variables EDU 5900 AB RAHIM BAKAR
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Simple factorial design
The interest is on the effect of a single independent variable but must also consider other variable that may influence the dependent variable. Typically these variables are attribute variable such as race, gender, SES, etc. Enable the researcher to study several relationship with one set of data Able to study interaction between variables EDU 5900 AB RAHIM BAKAR
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The simplest factorial design is 2 X 2 Factorial Design
The simplest factorial design is 2 X 2 Factorial Design. Here you have two independent variables with two levels each Method of teaching Class size Inquiry Method Lecture Method Mean Small 46 38 45 large 40 32 36 43 35 Example A EDU 5900 AB RAHIM BAKAR
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In example, the inquiry method is shown to be superior in both small and large classes. Hence there is no interaction effect. Regardless of class size, inquiry method is superior than lecture method. There is no interaction 50 46 45 inquiry What is interaction effect? The effect obtained may be differ for a different group. The result is moderated by another variable 40 40 38 35 lecture 30 32 small large EDU 5900 AB RAHIM BAKAR
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Method of teaching Class size Method A Method B Mean Small 48 42 45
Example B Method of teaching Class size Method A Method B Mean Small 48 42 45 large 32 38 36 40 EDU 5900 AB RAHIM BAKAR
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small class than in large Class with both methods.
Studenst did better in small class than in large Class with both methods. However, students in small Class did better when taught Using inquiry method. Students in large class Did better when taught using Lecture method. Here there is an interaction between Class size and teaching methods 50 48 45 inquiry 42 40 38 lecture 35 30 32 small large EDU 5900 AB RAHIM BAKAR
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There is an interaction between class size and methods
Even though students in small class did better than those in large class, how well depends on the method used. As a result the researcher may conclude that effectiveness of the method is dependent on the class size. There is an interaction between class size and methods If factorial design was not used, you may conclude that there is no effect of method on achievement (40, 40) EDU 5900 AB RAHIM BAKAR
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Moderator variable : (1) small class and (2) large class.
You can have a more complicated factorial design such as n BY n Factorial Design Example: (1) CAI, (2) Lecture-Discussion (3) Television Lecture (4) Quite Reading Moderator variable : (1) small class and (2) large class. 3X3 or 4X2 or 3X2 EDU 5900 AB RAHIM BAKAR
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