Flashcards in Definitions of Key terms Deck (7)
An aim identifies the purpose of the investigation. It is a straightforward expression of what the researcher is trying to find out from conducting an investigation. The aim typically involves the word “investigate” or “investigation”.
Define alternative hypothesis (directional and non-directional)
•The alternative hypothesis states that there is a relationship between the two variables being studied (one variable has an effect on the other). It states that results are not due to chance and that they are significant in terms of supporting the theory being investigated
A nondirectional alternative hypothesis states that the null hypothesis is wrong. A nondirectional alternative hypothesis does not predict whether the parameter of interest is larger or smaller than the reference value specified in the null hypothesis.
- A directional alternative hypothesis states that the null hypothesis is wrong, and also specifies whether the true value of the parameter is greater than or less than the reference value specified in null hypothesis.
- The advantage of using a directional hypothesis is increased power to detect the specific effect you are interested in. The disadvantage is that there is no power to detect an effect in the opposite direction.
Define the null hypothesis
The null hypothesis states that there is no relationship between the two variables being studied (one variable does not affect the other). It states results are due to chance and are not significant in terms of supporting the idea being investigated.
What is the difference between a one tailed and two tailed hypothesis?
one-tailed directional hypothesis predicts the nature of the effect of the independent variable on the dependent variable.
• E.g.: Adults will correctly recall more words than children.
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.
• E.g.: There will be a difference in how many numbers are correctly recalled by children and adults
Define Pilot studies
•A pilot study is an initial run-through of the procedures to be used in an investigation; it involves selecting a few people and trying out the study on them. It is possible to save time, and in some cases, money, by identifying any flaws in the procedures designed by the researcher.
•A pilot study can help the researcher spot any ambiguities (i.e. unusual things) or confusion in the information given to participants or problems with the task devised.
•Sometimes the task is too hard, and the researcher may get a floor effect, because none of the participants can score at all or can complete the task – all performances are low. The opposite effect is a ceiling effect, when the task is so easy that all achieve virtually full marks or top performances and are “hitting the ceiling”.
Define Demand Characteristics
A demand characteristic is a subtle cue that makes participants aware of what the experimenter expects to find or how participants are expected to behave. Demand characteristics can change the outcome of an experiment because participants will often alter their behaviour to conform to the experimenters expectations.