Psychology Research Methods - scientific processes
Aims and hypothesis:
Key words:
➢ Aim = a general statement about what the study intends to investigate
➢ Hypothesis = a precise testable statement including levels of IV and DV
● Null Hypothesis -
There is no change (difference) in the measurement of the DV as a result of the manipulation in the IV
● Alternative Hypothesis -
A testable statement used in a non-experimental method to predict what will happen in an
investigation.
Known as the research hypothesis - states that there is a change (difference) in the measurement of the
dependent variable as a result of the manipulation in the independent variable.
● Directional hypothesis -
A hypothesis that predicts a very specific direction of outcome of a study.
E.g., one thing will be greater than or faster than the other
● Non-directional hypothesis -
A hypothesis that does not state a specific direction of outcome of a study.
E.g., one thing will affect the other thing
Hypothesis testing - data is collected and statistical testing is conducted on the data.
- This provides evidence, if the evidence is strong enough the null hypothesis can be rejected
and the alternate hypothesis is accepted
---------------------------------------------------------------------------------------------------------------------------
Pilot studies:
A small scale practice investigation, conducted before the full research
- Used to identify problems with: design methodology, analysis and gain feedback
- Can check if participants don’t understand certain questions/instructions/taks
- Can see if participants figure out the aim (demand characteristics)
- More affordable
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Demand characteristics and investigator effects:
➢ Demand characteristics = subtle clues that make participants aware of what the researcher
expects to find, or how the participants are supposed to behave
➢ Investigator effects = the ways that researchers can influence the results of their research
(e.g., unconscious bias)
Reducing investigator effects:
1. Single Blind - participant does not know the true aims of experiment, but experimenter does
2. Double Blind - both participants and experimenter don’t know the aims of the study
- meaning the investigator cannot give any clue
, Sampling:
Key word:
➢ Sampling = participants selected from a target population to take part in research
➢ Population = wider group of people identified as those that findings should apply to
➢ Target population = every member of the group that the investigator plans to study.
- As the target population could contain millions of people they cannot all be studied
● Random sampling - Each member of the target population has a mathematically equal chance
of being in the experiment’s sample
(S) - avoids researcher bias - researcher cannot choose participants they want to form the sample,
avoiding the possibility the researcher picks participants they feel are likely to give a preferred result
…………………………………………………………………………………………………………………..
(L) - unrepresentative sample - e.g., too few members of one gender or with no members of a
minority group
(L) - time consuming - can be difficult to get a full list of a target population
● Systematic sampling - participants are chosen from a list. Every nth participant is chosen
(S) - avoids researcher bias
(S) - quick method of selecting a sample - if there is an existing list of the target population
…………………………………………………………………………………………………………………..
(L) - could result in an unrepresentative sample
(L) - if the target population is very large - getting a full list could be difficult
● Opportunity sampling - researcher directly asks available members of the target population to
take part in in the research
- Likely individuals the researcher can easily access (e.g., university students)
(S) - fastest way to get a sample - reduces the time it takes to conduct research and likely reducing
the cost involved compared to more complex sampling methods
…………………………………………………………………………………………………………………..
(L) - researcher bias - the researcher decides who to task to take part in the study. Meaning they may
select participants they feel are likely to produce a preferred result
(L) - not representative - as participants chosen are the type of people the researcher can easily
access (young undergrad students)
Aims and hypothesis:
Key words:
➢ Aim = a general statement about what the study intends to investigate
➢ Hypothesis = a precise testable statement including levels of IV and DV
● Null Hypothesis -
There is no change (difference) in the measurement of the DV as a result of the manipulation in the IV
● Alternative Hypothesis -
A testable statement used in a non-experimental method to predict what will happen in an
investigation.
Known as the research hypothesis - states that there is a change (difference) in the measurement of the
dependent variable as a result of the manipulation in the independent variable.
● Directional hypothesis -
A hypothesis that predicts a very specific direction of outcome of a study.
E.g., one thing will be greater than or faster than the other
● Non-directional hypothesis -
A hypothesis that does not state a specific direction of outcome of a study.
E.g., one thing will affect the other thing
Hypothesis testing - data is collected and statistical testing is conducted on the data.
- This provides evidence, if the evidence is strong enough the null hypothesis can be rejected
and the alternate hypothesis is accepted
---------------------------------------------------------------------------------------------------------------------------
Pilot studies:
A small scale practice investigation, conducted before the full research
- Used to identify problems with: design methodology, analysis and gain feedback
- Can check if participants don’t understand certain questions/instructions/taks
- Can see if participants figure out the aim (demand characteristics)
- More affordable
---------------------------------------------------------------------------------------------------------------------------
Demand characteristics and investigator effects:
➢ Demand characteristics = subtle clues that make participants aware of what the researcher
expects to find, or how the participants are supposed to behave
➢ Investigator effects = the ways that researchers can influence the results of their research
(e.g., unconscious bias)
Reducing investigator effects:
1. Single Blind - participant does not know the true aims of experiment, but experimenter does
2. Double Blind - both participants and experimenter don’t know the aims of the study
- meaning the investigator cannot give any clue
, Sampling:
Key word:
➢ Sampling = participants selected from a target population to take part in research
➢ Population = wider group of people identified as those that findings should apply to
➢ Target population = every member of the group that the investigator plans to study.
- As the target population could contain millions of people they cannot all be studied
● Random sampling - Each member of the target population has a mathematically equal chance
of being in the experiment’s sample
(S) - avoids researcher bias - researcher cannot choose participants they want to form the sample,
avoiding the possibility the researcher picks participants they feel are likely to give a preferred result
…………………………………………………………………………………………………………………..
(L) - unrepresentative sample - e.g., too few members of one gender or with no members of a
minority group
(L) - time consuming - can be difficult to get a full list of a target population
● Systematic sampling - participants are chosen from a list. Every nth participant is chosen
(S) - avoids researcher bias
(S) - quick method of selecting a sample - if there is an existing list of the target population
…………………………………………………………………………………………………………………..
(L) - could result in an unrepresentative sample
(L) - if the target population is very large - getting a full list could be difficult
● Opportunity sampling - researcher directly asks available members of the target population to
take part in in the research
- Likely individuals the researcher can easily access (e.g., university students)
(S) - fastest way to get a sample - reduces the time it takes to conduct research and likely reducing
the cost involved compared to more complex sampling methods
…………………………………………………………………………………………………………………..
(L) - researcher bias - the researcher decides who to task to take part in the study. Meaning they may
select participants they feel are likely to produce a preferred result
(L) - not representative - as participants chosen are the type of people the researcher can easily
access (young undergrad students)
