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How Science Works
Experimental method
Experimental Process
1. Ask questions and develop theories about how, why and where things happen
2. Develop these into a specific hypothesis (predictions)
3. Design & Carry out research to test these theories – what happens when we try it out?
Experimental Process
Findings support or refute theory = refine theory
Hypotheses• 2 types:
Experimental Hypothesis(Alternative Hypothesis)
- A prediction of the outcome
Null Hypothesis
-Findings are due to chance
-There is no relationship or difference as predicted
Try writing an Experimental & Null hypothesis for these possible
studies1. A study that aims to look at the effect of music
on concentration
2. A study that aims to look at the amount of TV a child watches and their behaviour at school
3. A study that aims to see whether a task, such as counting backwards from the number 15 after seeing a list of letters, will affect the ability to recall of those letters
Experimental Hypotheses
You may wish to predict the direction of the effect = Directional / One-tailed
e.g.– Students’ performance will improve with practice– Eating chocolate will increase happiness– Taking regular exercise will decrease risk of heart
disease
• Alternatively, you can just say that there will be an effect = Non-directional / Two-tailed
Examples
1. Students remember more words when recalling them in the same location in which they were learnt than when in a different location.
2. Recall of a story is affected by the length of time since hearing the story.
• Experiments are one of the most commonly used methods in psychology
• An experiment is a research method in which the researcher – the experimenter – has a high degree of control.
• The experimenter controls/manipulates the independent variable (IV) and measures the dependent variable (DV)
Experimental Process
Example
• If we were to conduct an experiment on whether television distracts students from studying, what would be the IV and the DV?
HINT:Look for what is being measured (DV)
first, IV is then easy to identify!
• Both IV & DV MUST be measurable = Operationalise
• There are usually two values of the IV e.g.– Noise or no noise– Smoker or non-smoker– Male or Female
• These determine the conditions of the experiment
• The conditions can be arranged in several different ways (There can be more than 2 conditions)
Other variables• What else might affect the study?
• Any variable (except for the IV) that can influence your findings = extraneous variables
E.g. Participant Variables = age, gender,
experience, emotionSituational Variables = noise, light, time
of day, crowds, interruptions
• If an extraneous variable is NOT controlled for and impacts the results =
Confounding variable