research methods

• a directional hypothesis states the direction of the relationship between the variables
• a non directional hypothesis is a hypothesis that states that there is no difference between the two groups
• a null hypothesis states that there is no significant effect in a study
• the experimental method involves manipulating one variable to determine if these changes cause changes in another variable
• the aim is the studys objective
• a hypothesis is a testable and predictive statement
• one tailed is directional
• two tailed is non directional
• null = no significant difference
• the independant variable is the one that is changed and the dependant variable is the one that is measured
• alcohol affects reaction time is an example of a non-directional hypothesis
• boys are more aggressive than girls is a directional hypothesis
• independent measures is where different participants are used in each condition of the experiment
• one strength of independent measures is that it avoids order effects
• one disadvantage of independent measures is more participants are required
• repeated measures is where the same participants take part in both conditions
• one advantage of repeated measures is that fewer participants are needed
• one disadvantage of repeated measures is order effects have an effect on participants behaviour
• matched pairs is 2 participants who are matched on a variable and then put into two separate groups
• one advantage of matched pairs is that is reduces participant variables and order effects
• one weakness of matched pairs is that its very time consuming
• a lab experiment is experiments that are done in highly controlled environments that aren't always done in a lab
• strengths of a lab experiment are a high control on extraneous variables and replication is more possible
• weaknesses of a lab experiment are the artificiality of the environment, low ecological validity and it may not be representative of real life situations
• field experiments are experiments conducted outside of the laboratory where there is no manipulation or random allocation to conditions
• strengths of field experiments are they have higher ecological validity as they take place in natural settings
• disadvantages of field experiments include lack of control over extraneous variables which can affect results
• Natural experiments are where the researcher does not exert any influence over the situation but rather simply observes individuals and circumstances
• one strength of natural experiment is high external validity
• one limitation of a natural experiment is it is difficult to control extraneous variables
• a quasi experiment is research that resembles experimental research but is not true experimental research
• one strength of a quasi experiment is that they are often carried out under controlled conditions and therefore share some strengths of a lab experiment
• one limitation of a quazi experiment is that participants cannot be randomly allocated to conditions
• demand characteristics influence participants behaviour based on wether or not they know its an experiment
• we deal with demand characteristics through single blind design which is where they are unaware of which condition their in
• investigator effects are biases in research outcomes caused by the behaviour or expectation of the researcher
• we deal with investigator effects through the double blind design - both person conducting the experiment and participants are blind to hypothesis
• situational variables are features of a research situation that may influence participants behaviour
• we deal with situational variables by standardising and counterbalancing
• participant variables are individual characteristics of participants that can influence the results of a study