Experimental Method

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Example - Energy Drink Experiment:

There is a theory based on internet research that energy drinks affect how much people talk. In psychological experiments aims are developed from theories. Therefore;

Aim: to investigate whether drinking energy drinks makes people more talkative

The next step is to develop a hypothesis;

Directional Hypothesis: People who drink energy drinks become more talkative than people who don't

Non Directional Hypothesis: People who drink energy drinks differ in terms of talkativeness compared with people who don't drink energy drinks

Deciding which type of hypothesis to use;

Psychologists tend to use a directional hypothesis when the findings of previous research studies suggest a particular outcome. When there is no previous research or findings from earlier studies are contradictory, a non-directional hypothesis is used. In the case of the energy drink study, a directional hypothesis is used.

Doing the experiment;

Gather two groups of participants with 10 people in each group, and give the first group an energy drink to drink and the second group a glass of water to drink. Then record how many words each participant says in a five minute period.

Independent and dependent variables;

In an experiment a researcher changes/manipulates the independent variable and records/measures the effect of this change on the dependent variable. All other variables that may potentially affect the DV should remain constant. This is so the researcher can be confident that the cause of the effect on the DV was the IV and the IV alone.

Levels of the IV;

In order to test the effet of the IV you need different experimental conditions. Therefore;

Compare 2 groups of participants - those who drink energy drinks with those who drink water

Operationalisation of variables;

Operationalisation means defining variables to give them a measurable value so the results can be clearly analysed. Therefore an operationalised hypothesis would be;

After drinking 300ml of energy drink participants say more words in the next 5 minutes than participants who drink 300ml of water