What is a laboratory experiment?
an experiment carried out in a controlled setting,
What is a field experiment
a controlled experiment conducted outside a laboratory, the iv is still manipulated by the experimenter therefore casual relationships can be demonstrated
advantages and disadvantages of laboratory experiments
+ high internal validity as they have good control over all variables - the change in the DV is more likely due to the manipulation of the IV
- low ecological validity as participants are aware they are being studied so will behave differently and the tasks are more artificial
advantages and disadvantages of field experiments
What is a natural experiment
a research method in to which experimenter has not manipulated the iv directly, the IV would vary whether or not the researcher was interested and they would record the results of the dv
What is a Quasi-experiment?
studies that are almost experiments but the independent variable is not something that varies at all but a condition that exists, the researcher records the effect on the dv
give an example of a Quasi-experiment?
gender differences
age
what are the advantages and disadvantages of a natural experiment
+ allows research where the iv cant be manipulated for ethical or practical reasons
+ allows researches to study real problems such as the effects of a disaster on health
- cannot demonstrate casual relationships because IV is not directly manipulated
- random allocation not possible therefore there may be confounding variables that cannot be controlled lowering internal validity
What are the advantages and disadvantages of a quasi-experiment?
+ allows comparisons between types of people
what is an opportunity sample method and what are the strengths and weaknesses
this is when you recruit people who are the most convinenet or most available
+ easiest as takes less time to find the participants
- biased as sample drawn from small part of the population
what is an random sample sample method and what are the strengths and weaknesses
producing a sample of participants by using random techniques
+ unbiased all members of target population have a chance of getting selected
- need to have a list of all memebers of the population then contact them this could take time
what is an stratified sample method and what are the strengths and weaknesses
subgroups within a population are identified, the participants are chosen from each of the strata in proportion to their occurrence in the population, the selection from the strata is done using a random technique
+ more representative
- time consuming to identify all the groups
what is an systematic sample method and what are the strengths and weaknesses
a predetermined system to select participants such as selecting every 2nd person, the numerical interval is applied consistently
+ unbiased as participants selected using an objective system
- not truly unbiased unless you select a number using a random, method and start with this person
what is an volunteer sample method and what are the strengths and weaknesses
advertise in a newspapaer or on the noticeboard
+ gives access to a variety to participants
- sample is biased as participants are more likely to be highly motivated and have extra time on their hands
describe the lottery method
describe the random number table
describe random number generators
2. use calculator or electronic hat
what is a sample bias
in fact that even though all samples try to reduce bias they are eventually all disorted
what is a volunteer bias
a form of sampling bias because volunteer participants have special characteristics such as being highly motivated
what are the ethical issues
described informed consent
describe decpetion
right to withdraw
protection from physical and psychological harm