9] Intro To Experimental Design Flashcards
Types of validity
1: face
2: content
3: construct
4: criterion related
What is external validity
The extent to which you can generalise the findings of a study to other situations, people, settings and measures
What is internal validty
The extent to which the observed results represent the truth in the population we are study and thus are not due to methodological errors
What is the three conditions for causation
1: there is a relationship between the two variables
E.g: do people who study more (variable A) do better on exams (variable B)
2: A must precede B
E.g: study comes before the grade of the exam
3: there is no confounding variables explaining the relationship
E.g: perhaps motivation influences how well they do in the exam and how much they study
What are true experiments
It is an experiment conducted to prove or disprove a cause and effect relationship between two variables
It must include a control group and at least one experimental group that are randomly assigned and a researcher manipulated variable
What are the four basic elements of true experiments
1: manipulation
2: measurement
3: control
4: comparison
True Experiments: What does manipulation mean
It is the manipulation you place on the independent variable, this is so you can identify the cause and effect relationship.
They will change a certain factor and then measure the outcome as a result of that change
E.g: Changing the wording of two different options for two separate group but still keeping their meanings the same, having one negatively and one positively worded to see what they pick
True Experiments: What does measurement mean
In this scenario it is discussing the outcome (dependent variable), and how we measure it.
We measure how that outcome has varied in data due to a set change and we do this because it helps clarify the relationship between the dependent variable and independent variable.
E.g: Out of the two groups the outcome is how many of them choose the option A or the option B depending on the wording (independent variable)
True Experiments: What does control mean
This is the control you have over all the other variables (extraneous variables) in a true experiment, having all conditions and factors in the test under your control and only changing a few variables
E.g: Both groups had a choice between only A and B, both of which were in the same order for each group
True Experiments: What does comparison mean
Once you have manipulated your independent variable, measured your dependent variable accordingly and controlled all other extraneous variables you now must compare the results of the diffrent experimental conditions.
We do this so we can establish the relationship between the manipulated independent variable, and the dependent variables change in accordance to its manipulation.
E.g: Comparing the results of the two groups choice of either option A or B
What is an independent variable
It is the variable you manipulate or vary in an experimental study to explore its effects
What is a dependent variable
It is the variable that is being measured or tested in an experimental study due to a manipulation of the independent variable
What is an extraneous variable
It is any variable not being investigated that has the potential to affect the outcome of a research study by impacting the conditions without being manipulated
What is a confounding variable
It is an unmeasurable third variable that influences both the cause (independent variable) and supposed effect (dependent variable), without removing them you research is susceptible to biases and can lead you to misinterpret your findings
How does an extraneous variable become a confounding variable
1: they impact the dependent variable
2: they must vary systematically with the independent variable
