Research Methods AS/A2

Research Methods

Aim – The aim of the study is what the study is trying to find out. 

Hypothesis - A hypothesis is a precise, testable statement of what the researchers predict will be the outcome of the study. This usually involves proposing a possible relationship between two variables: the independent variable (what the researcher changes) and the dependant variable (what the research measures).

·         The null hypothesis states that there is no relationship between the two variables being studied (one variable does not affect the other).

·         The alternative hypothesis states that there is a relationship between the two variables being studied (one variable has an effect on the other).

A directional prediction of what we expected to happen.

·         A one-tailed directional hypothesis predicts the nature of the effect of the independent variable on the dependent variable.

·         A two-tailed non-directional hypothesis predicts that the independent variable will have an effect on the dependent variable, but the direction of the effect is not specified.

A good hypothesis is short and clear and should include the operationalized variable being investigated. A variable is operationalised when it has been turned into something that can be measure.

Independent variable (IV): Variable the experimenter manipulates (i.e. changes) – assumed to have a direct effect on the dependent variable.

Dependent variable (DV): Variable the experimenter measures, after making changes to the IV that are assumed to affect the DV.

Operational variables (or operationalizing definitions) refer to how you will define and measure a specific variable as it is used in your study.

Extraneous variables – These are all variables, which are not the independent variable, but could affect the results (e.g. dependent variable) of the experiment.

Confounding variables -variables that have affected the results (DV), apart from the IV. A confounding variable could be an extraneous variable that has not been controlled.

There are four types of extraneous variables:

Situational Variables

These are aspects of the environment that might affect the participant’s behaviour, e.g. noise, temperature, lighting conditions, etc. Situational variables should be controlled so they are the same for all participants.

Standardized procedures are used to ensure that conditions are the same for all participants. This includes the use of standardized instructions

Participant / Person Variable

This refers to the ways in which each participant varies from the other, and how this could affect the results e.g. mood, intelligence, anxiety, nerves, concentration etc.

For example, if a participant that has performed a memory test was tired, dyslexic or had poor eyesight, this could affect their performance and the results of the experiment. The experimental design chosen can have an effect on participant variables.

Situational variables also include order effects that can be controlled using counterbalancing, such as giving half the participants condition 'A' first, while the other half get condition 'B' first. This prevents improvement due to practice, or poorer performance due to boredom.

Participant variables can be controlled using random allocation to the…