HOW SCIENCE WORKS

1. HOW SCIENCE WORKS IDENTIFYING VARIABLES AND DESIGNING INVESTIGATIONS

2. IDENTIFYING VARIABLES AND DESIGNING INVESTIGATIONS The INDEPENDENT VARIABLE • Also known as the INPUT variable. • This is the thing that you change or manipulate, the thing you are testing.

3. IDENTIFYING VARIABLES AND DESIGNING INVESTIGATIONS The DEPENDENT VARIABLE • Also known as the OUTPUT variable. • This is the thing that you measure or observe, it’s the results of the experiment. • You expect the dependent variable to be affected by the independent variable.

4. IDENTIFYING VARIABLES AND DESIGNING INVESTIGATIONS The CONTROL VARIABLES • Any variable that you keep the same in order to allow for a ‘fair test’.

6. IDENTIFYING VARIABLES AND DESIGNING INVESTIGATIONS Example No. 1 • A student thinks that year 10 students will be better at doing a quiz than year 8 students. • Task 1: Write down the independent, dependent and control variables in this experiment.

7. IDENTIFYING VARIABLES AND DESIGNING INVESTIGATIONS Example No. 1 • Independent variable = the year group the students are in (year 10 or year 8) • Dependent variable = the students scores on the quiz

8. IDENTIFYING VARIABLES AND DESIGNING INVESTIGATIONS Example No. 1 • Control variables = the same quiz should be used, students should have the same amount of time to complete it.

10. IDENTIFYING VARIABLES AND DESIGNING INVESTIGATIONS Example No. 2 • A student has made the following prediction for an experiment; “the more caffeine I drink the quicker my reaction times will be.” • Task 2: What are the independent, dependent and control variables in this experiment.

11. IDENTIFYING VARIABLES AND DESIGNING INVESTIGATIONS Example No. 2 • Independent variable = the amount of caffeine drunk by the student (e.g. number of cups of cola) • Dependent variable = the students reaction times (e.g. how quick they can catch a ruler)

12. IDENTIFYING VARIABLES AND DESIGNING INVESTIGATIONS Example No. 2 • Control variables = the same type of drink, same method of measuring reaction time.

14. IDENTIFYING VARIABLES AND DESIGNING INVESTIGATIONS Example No. 3 • The light intensity was measured at different points moving away from the trunk of a large tree in full leaf. • Task 3: What are the independent, dependent and control variables in this experiment.

15. IDENTIFYING VARIABLES AND DESIGNING INVESTIGATIONS Example No. 3 • Independent variable = the distance from the tree trunk. • Dependent variable = the light intensity.

16. IDENTIFYING VARIABLES AND DESIGNING INVESTIGATIONS Example No. 3 • Control Variables = the same tree used for all measurements, the same light intensity meter, the same day/weather conditions.

18. IDENTIFYING VARIABLES AND DESIGNING INVESTIGATIONS Designing an experiment. • What is the optimum temperature needed for the enzyme amylase to work? • Task 4: design an experiment to test this hypothesis • What are the independent and dependent variables? How will you make it a fair test? How many different temperatures will you test? How will you measure the results?

21. EXPERIMENTAL RESEARCH • An experiment that involves the manipulation of one or more variables as well as the measurement of the effects of such manipulation or behavior.

22. CONDITIONS FOR EFFECTIVE EXPERIMENT

23. CONDITIONS FOR EFFECTIVE EXPERIMENT CONTROLis a group that is not exposed to a chemical or treatment being investigated so that it can be compared with experimental groups that are exposed to the chemical or treatment (standard of comparison)

24. CONDITIONS FOR EFFECTIVE EXPERIMENT RANDOM ASSIGNMENT this is formed prior to the introduction of the independent variables. This is the placing of the sample subject in the condition of the experiment.

25. CLASSIFICATION OF EXPERIMENTS QUASI - EXPERIMENT TRUE EXPERIMENT

26. TRUE EXPERIMENTAL R. an experiment that leads to an unambiguous outcome regarding what caused an event

27. IMPORTANT CHARACTERISTICS OF TRUE EXPERIMENTAAL RESEARCH

28. IMPORTANT CHARACTERISTICS OF TRUE RESEARCH Some type of intervention or treatment is implemented.

29. IMPORTANT CHARACTERISTICS OF TRUE RESEARCH The experimenter has a high degree of control over the arrangement of experimental conditions, assignment of participants, systematic manipulation of independent variables and choice of dependent variables.

30. IMPORTANT CHARACTERISTICS OF TRUE RESEARCH Assign random participants in the experimental research (the most important characteristic)

31. IMPORTANT CHARACTERISTICS OF TRUE RESEARCH There is an appropriate comparison in order to evaluate the effectiveness of a treatment.

32. EXPERIMENTAL DESIGNS

33. TRUE EXPERIMENTAL RESEARCH

34. FREQUENTLY USED TRUE EXPERIMENTAL DESIGN • PRE-TEST- POST TEST CONTROL GROUP DESIGN • POST-TEST ONLY CONTROL GROUP DESIGN

35. PRE-TEST- POST TEST CONTROL GROUP DESIGN • The EXPERIMENTAL GROUP is given an intervention or treatment, whereas the CONTROL GROUP is left alone or given another kind of intervention.

36. PRE-TEST- POST TEST CONTROL GROUP DESIGN • Before the intervention is given a PRE-TEST is given to the CONTROL and EXPERIMENTAL GROUPS. (BASELINE DATA)

37. PRE-TEST- POST TEST CONTROL GROUP DESIGN • After the intervention is given a POST-TEST is given to the CONTROL and EXPERIMENTAL GROUPS with the same instrument used to both groups. (ENDLINE DATA)

38. PRE-TEST- POST TEST CONTROL GROUP DESIGN • The BASELINE and ENDLINE results are compared. “PARALLEL GROUP TECHNIQUE” E.G. O1 O3 C.G. O2 O4 x

39. POST TEST ONLY CONTROL GROUP DESIGN • At the start of the experiment the CONTROL and EXPERIMENTAL GROUPS have similar characteristics. • The E.G. is given intervention while the CONTROL GROUP is left alone.

40. POST TEST ONLY CONTROL GROUP DESIGN • There is no Pre-Test or Pre-intervention conducted. • After the intervention is given to the Experimental Group. A POST TEST is conducted to both groups.

41. QUASI-EXPERIMENTAL RESEARCH

42. QUASI-EXPERIMENT • semi | partial • it lacks some properties of a true experiment (RANDOMIZATION, control group, validity component)

43. QUASI-EXPERIMENT • Validity of the cause and effect inferences may be challenged since only human judgment rather than objective criteria is utilized in reaching a decision.

44. RANDOMIZATION • is a process of getting a sample such that every individual that comprises the population will be given an equal chance to be included as sample; no control group is used as basis for comparison.

45. WHAT DO YOU THINK IS THE EFFECT OF THE ABSENCE OF THE CONTROL GROUP?

46. QUASI-EXPERIMENTAL RESEARCH DESIGN • NON-EQUIVALENT CONTROL GROUP DESIGN • TIME-SERIES DESIGN

47. NON-EQUIVALENT CONTROL GROUP DESIGN • a study design in which the control group is NOT selected by random means.

48. "NONEQUIVALENT" MEAN? • the researcher did not control the assignment to groups through the mechanism of random assignment.

49. NON-EQUIVALENT CONTROL GROUP DESIGN • PRE-TEST is conducted to both Experimental Group (O1) and Control Group (O2) before the Treatment.

50. WHAT IS THE IMPORTANCE OF PRE-TEST? • The PRE-TEST is used to determine that the two groups have collective similarity at the start of the experiment.