Hypothesis and IV and DV
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Transcript of Hypothesis and IV and DV
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