The experimental method Flashcards
Explain what is meant by the term ‘directional hypothesis’ (2 marks)
A directional hypothesis is a form of alternate hypothesis.
It is used when previous research has been conducted and was conclusive in a particular direction. The hypothesis predicts which way the results of the research will go.
Explain the difference between an extraneous variable and a confounding variable (3 marks)
Extraneous variables are nuisance variables that do not vary systematically with the IV (and therefore affect everyone in different ways). They do not confound the results of the study but rather ‘muddy’ the waters.
Confounding variables do vary systematically with the IV so the researcher cannot be sure if any observed change in the DV is due to the manipulation or the confounding variable.
Outline what is meant by the term ‘investigator effects’. Explain why these should be controlled in a research study. (4 marks)
Investigator effects refers to any unwanted influence of the investigator’s behaviour on the outcome of the research (DV). Examples of investigator effects include the greenspoon effect, interviewer bias & any bias in the selection of the participants.
It is important to control investigator effects as they make the experiment less internally valid - the investigator’s behaviour may contribute to any changes in the DV meaning that it is difficult to determine causal relationships between the IV and the DV.
Explain one advantage of using a repeated measures design (2 marks)
An advantage of using repeated measures is that participant variables are not an issue. Because each participant completes both conditions of the IV, the person in both conditions have the same characteristics which controls an important confounding variable (makes cause and effect difficult to establish)
Explain what is meant by the term ‘reliability’ and how it can be checked (3 marks)
Reliability refers to consistency over time. If a study is reliable, similar results would be obtained if the study was conducted again.
You can check for reliability by conducting the study again (test-retest) and see if similar results are obtained. the second time. A strong correlation between the two scores would indicate reliable data.
Explain what is meant by the term ‘validity’ (1 marks)
Validity refers to how accurate or legitimate something is and determines if the researcher is measuring what they set out to measure.
Explain how you can determine if two observers have ‘inter-rater reliability’. (4 marks)
The two observers should familiarise themselves with the behavioural categories in the observation. They should then observe the same behaviour at the same time (potentially as part of a small scale pilot study). They should then compare the data and discuss any differences. Finally, inter-rater reliability is calculated by correlating each pair of observations make and an overall figure is produced.
Explain what is meant by an EV and why it is important to control them (3 marks)
An extraneous variable is a variable other than the IV that may have an effect on the DV - does not vary systematically with the IV though.
It is important to control EVs as they make the experiment less internally valid - the EV may be responsible for any changes in the DV meaning that it is difficult to determine causal relationships between the IV and the DV.
