Educational Research. S.Shafiee. Expert PDF Trial

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1 Educational Research: Experimental Studies Educational Research S.Shafiee

2 Research... The systematic application of a family of methods employed to provide trustworthy information about problems an ongoing process based on many accumulated understandings and explanations that, when taken together lead to generalizations about problems and the development of theories

3 experimental research the researcher selects participants and divides them into two or more groups having similar characteristics and, then, applies the treatment(s) to the groups and measures the effects upon the groups

4 Conducting an experimental study 1. select the problem 2. select participants and instrument 3. selection and execution of a research plan 4. data analysis and formulation of conclusions

5 Characteristics of experimental research Control Manipulation Observation

6 Confounding the fact that the effects of the independent variable may intertwine with extraneous variables, such that it is difficult to determine the unique effects of each variable

7 Types of experimental comparison 1. comparison of two different approaches (A versus B) 2. comparison of an existing approach to a new approach (A and ~ A) Placebo treatment

8 where: A experimental ( treatment ) group B control ( no treatment, nonmanipulated ) group

9 The concept of validity the experiment tests the variable(s) that it purports to test

10 Internal validity The extent to which the changes observed in a dependent variable are caused by the independent variable in a particular experimental situation

11 Threats to internal validity 1. history 2. maturation 3. testing 4. instrumentation 6. differential selection of participants 7. Mortality and attrition

12 history the occurrence of events that are not part of the experimental treatment but that occur during the study and affect the dependent variable

13 maturation the physical, intellectual, and emotional changes that occur naturally in a study s participants over a period of time

14 testing refers to improved scores on a posttest as a result of having taken a pretest

15 mortality the case in which participants drop out of a study which changes the characteristics of the groups and may significantly affect the study s results

16 selection-maturation interaction if already-formed groups are used in a study, one group may profit more (or less) from a treatment or have an initial advantage because of maturation, history, or testing factors

17 external validity Generalizability or representativeness of the findings The extent to which the results of an experiment can be generalized to different subjects, settings and situations.

18 There is a trade-off between external and internal validity.

19 single-variable designs involve one manipulated independent variable pre-experimentalexperimental quasi-experimental true experimental

20 Pre-Experimental Designs: No Control Group and/or Randomization

21 types of pre-experimental experimental designs one-shot case study X T a single group exposed to a treatment ( X ) and then posttested ( T)

22 one-group pretest-posttest posttest design T1 X T2 a single group is pretested ( T1 ), exposed to a treatment ( X ) and, then, is posttested ( T2 )

23 Static/intact group comparison G1 G2 O X T T involves at least two groups ( G1 and G2 ), one receiving a new, or experimental treatment ( X 1 ) and another receiving a traditional, or control treatment ( O ) and, then, are posttested ( T )

24 types of quasi-experimental designs Trial PDF equivalent time sample O X O )Expert random assignment of intact groups that are pretested ( O ), exposed to a treatment ( X ) and then posttested ( O

25 time-series design T1 T2 T3 X T4 T5 T6 a single group is pretested (T1 T2 T3 )repeatedly until pretest scores are stable, exposed to a treatment ( X ) and, then, is repeatedly posttested (T4 T5 T6 )

26 T1 Equivalent time design X T2/T3 O T4/T5 X T6/T7 O T8 After and before the treatment there is a test. After the second pretest (T3) a placebo is introduced followed by a posttest. This procedure is repeated and the scores obtained after applying treatment is compared with scores after the placebo.

27 Mini-Quiz True and false experimental researcher is the only type of research that can test hypotheses to establish cause-andeffect relationships True

28 True and false the manipulation of the independent variable is the one characteristic that differentiates correlational research from other types of research False

29 True and false an experimental study is guided by at least one hypothesis that states an expected causal relationship between two variables True

30 True and false the experiment in an experimental study is conducted to conform or disconfirm the research problem False

31 True and false experimental research has both random selection and assignment whereas causal-comparative research has random selection not assignment True

32 True and false it is correct to state that a control group always receives no treatment in experimental studies False

33 True and false in an experimental study, the researcher makes every effort to ensure that the two groups start as equivalently as possible on all variables except the independent variable True

34 True and false in an experimental study, the researcher collects data on the independent variable from the groups to determine whether there is a significant difference between their performances False

35 True and false in an experimental study, the researcher endeavors to make the groups as similar as possible so that the only major difference between them is the treatment variable(s) manipulated by the researcher True

36 True and false even though experimental research is the only type of research that can truly establish cause-effect relationships, it is not universally appropriate for all research problems or studies True

37 True and false an experiment is valid if results obtained are due only to the control variable and if they are generalizable to individuals or contexts beyond the experimental setting False

38 True and false internal validity focuses upon threats or rival explanations that influence the outcomes of an experimental study but are not part of the independent variable True

39 True and false if a study s results cannot be replicated in other settings by other researchers, then the study has low external reliability False

40 True and false to conduct a valid experiment, all the researcher has to do is to maximize internal and external validity False

41 True and false true experimental designs control for all sources of internal and external validity False

42 True and false the more narrowed and controlled a research situation is, the less realistic and generalizable it becomes True

43 True and false a study that is not internally valid is worthless True

44 True and false the longer a study lasts, the more likely it is that history will be a threat to the study s internal validity True

45 True and false the way a researcher controls for selection-maturation interaction is to select a design that controls for potential problems or to make every effort to determine if selection-maturation interaction is operating in the study True

46 True and false even if intact groups are randomly selected, the possibility exists that the experimental group is in some important way different from the control group and/or from the larger population True

47 True and false it is possible to know what a researcher means by the terms assigned to variables without clear operationalized descriptions False

48 True and false good designs control for many sources of invalidity, poor designs control few True

49 True and false a researcher should decide which research design is most appropriate not only by the controls provided but also by the nature of the study and the setting in which it is to be conducted True

50 True and false in a static-group comparison design, each group serves as a control or comparison group for the other group(s) True

51 True and false in a true experimental designs, participants should be randomly selected or randomly assigned False

52 True and false the more dissimilar the intact groups in a study are, the stronger the study is False

53 Fill in the blank the researcher decides what treatment(s) will constitute the independent variable and which group will get which treatment manipulation

54 Fill in the blank the researcher s efforts to remove the influence of any extraneous variable that might affect scores on the dependent variable control

55 Fill in the blank the researcher s concern with threats or factors other than the independent variable that affect the dependent variable internal validity

56 Fill in the blank the researcher s concern with the extent to which the study results can be generalized to groups and settings beyond those of the experiment external validity

57 Fill in the blank a threat to internal validity that may be overcome by testing for initial equivalence between groups differential selection of participants

58 Fill in the blank an external variable that effects the independent variable and intertwines with other extraneous variables such that it is difficult to determine the unique effects of each confounding variable

59 Fill in the blank a study to compare the achievement of two groups: one group taught in an anxiety-producing environment and one group taught in an anxietyreducing environment experimental

60 Fill in the blank the nonmanipulated variable in a factorial design control variable

Experimental Research. Types of Group Comparison Research. Types of Group Comparison Research. Stephen E. Brock, Ph.D.

Experimental Research. Types of Group Comparison Research. Types of Group Comparison Research. Stephen E. Brock, Ph.D. Experimental Research Stephen E. Brock, Ph.D., NCSP California State University, Sacramento 1 Types of Group Comparison Research Review Causal-comparative AKA Ex Post Facto (Latin for after the fact).