Question

Q#4:    Describe the important concepts relating to research design based on the understandings of dependent and independent variables, extraneous variable, control, confounded relationship and research hypothesis?

Mention the references at the end.

Solution to be typed up to 500 words.

Answer 1

Dependent Variable:-
The dependent variable is the effect. Its value depends on changes in the independent variable.

These other names of Dependent variable are more suitable somtimes :

• Explanatory variables (explians event or outcome).
• Predictor variables ( predict the value of a dependent variable).
• Right-hand-side variables (these variables appear on the right-hand side of a regression equation).

Independent Variable:-

The independent variable is the cause. Its value is independent of other variables in your study.

These other names of Independent variable are more suitable somtimes :

• Response variables (respond to a change in another variable)
• Outcome variables (these represent the outcome you want to measure)
• Left-hand-side variables (these appear on the left-hand side of a regression equation)

Extraneous variable:-

Extraneous variables are any variables that you are not intentionally studying in your experiment or research.

Types of Extraneous Variables

1. Demand characteristics: environmental clues which tell the participant how to behave, like features in the surrounding or researcher’s non-verbal behavior.
2. Experimenter / Investigator Effects: where the researcher unintentionally affects the outcome by giving clues to the participants about how they should behave.
3. Participant variables, like prior knowledge, health status or any other individual characteristic that could affect the outcome.
4. Situational variables, like noise, lighting or temperature in the environment.

                    confronting Variable

                    /\               |

                    |               |

                    |               V

        Activity level -------------> Dependent Variable

confounding variable:-

Confounding variables, which are also called confounders or confounding factors, are closely related to a study’s independent and dependent variables. A variable must meet two conditions to be a confounder:

• It must be correlated with the independent variable. This may be a causal relationship, but it does not have to be.
• It must be causally related to the dependent variable.

How to reduce the impact of confounding variables:

Restriction:-

In this method, you restrict your treatment group by only including subjects with the same values of potential confounding factors.

• Relatively easy to implemens

Matching:-

In this method, you select a comparison group that matches with the treatment group. Each member of the comparison group should have a counterpart in the treatment group with the same values of potential confounders, but different independent variable values.

• Allows you to include more subjects than restriction

Control:-

In an experiment the researcher forms or selects the groups under study, manipulates the treatments for the groups, attempts to to control extraneous or confounding variables.Two key components of this experimental process are manipulation and control.

In experimental and observational design and data analysis, the term control variable refers to variables that are not of primary interest (i.e., neither the exposure nor the outcome of interest) and thus constitute an extraneous or third factor whose influence is to be controlled or eliminated

Research hypothesis:-

A research hypothesis is a specific, clear, and testable proposition or predictive statement about the possible outcome of a scientific research study based on a particular property of a population, such as presumed differences between groups on a particular variable or relationships between variables

Elements of a Good Hypothesis

When trying to come up with a good hypothesis for your own research or experiments, ask yourself the following questions:

• Is your hypothesis based on your research on a topic?
• Can your hypothesis be tested?
• Does your hypothesis include independent and dependent variables?

Refrences:-

• https://www.scribbr.com/methodology/confounding-variables/
• https://www.statisticshowto.com/experimental-design/confounding-variable/
• https://conjointly.com/kb/hypotheses-explained/
• http://methods.sagepub.com/reference/encyc-of-research-design/n77.xml
• http://www.bwgriffin.com/gsu/courses/edur7130/content/experimental_research.htm
• https://www.statisticshowto.com/extraneous-variable/
• http://dissertation.laerd.com/extraneous-and-confounding-variables.php