Correlations & types of data Flashcards
What is meant by the term correlation?
- mutual relationship between two or more co-variables
What are co-variables?
- variables investigated within a correlation
What are the 3 types of correlations?
- positive
- negative
- zero
What is a positive correlation?
- as one co-variable increases the other also increases
- same trend observed
What is a negative correlation?
- as one co-variable increases the other decreases
What is a zero correlation?
- when there is no relationship between the co-variables
What are the differences between correlations ad experiments?
- in an experiment there is a manipulation of the IV in order to measure effect on DV > can infer cause & effect
- correlation there is no manipulation of one variable - can’t infer cause & effect between one co-variable & another
What are the strengths of using correlations?
- provided a precise & quantifiable measure of how two variables are related
- used as a starting point to assess possible patterns before researchers commit to study
- can use secondary data
- relatively quick & economical to carry out
- no need for controlled environment or manipulation of variables
What are the weaknesses of using correlations?
- correlation can only tell us how variables are related not why
- correlations cannot demonstrate cause & effect between variables
- third variable problem that could be causing relationship between two co-variables
- can be misused & misinterpreted
What is qualitative data?
- data that is expressed in words and may take form of a written description of thoughts, feelings & opinions of participants
What is quantitative data?
- data that is expressed numerically, usually in the form of individual scores from participants
Strengths and weaknesses of using qualitative data
strengths
- rich in detail & depth
- respondent can elaborate more fully
- greater external validity
weaknesses
- harder to compare & analyse
- produces subjective data
- may be subject to bias from researcher
Strengths & weaknesses of quantitative data
strengths
- easy to analyse & compare (convert into graphs & charts)
- tends to be more objective
- less open to bias
- representative
weaknesses
- lacks detail & depth
- fails to represent ‘real life’
What is primary data?
- original data that has been collected by a researcher for the purpose of their research
What is secondary data?
- data that has been collected by someone else and already exists before the psychologist begins their research
Strengths and weaknesses of collecting primary data
strengths:
- data is specific to the purpose of research
- up to data information
weaknesses:
- time consuming & effort required
- requires planning, preparation & resources (costly)
Strenghts and weaknesses of collecting secondary data
strengths:
- inexpensive
- easily accessed
weaknesses
- may not have all information/incomplete
- lacks quality
- content may not match researchers needs and objectives
What is a meta-analyis?
- process of combining findings from a number of studies on a particular topic to produce an overall statistical conclusion based on the range of studies
Strengths of conducting a meta-analysis
- allows you to create a larger, and much varied sample
- results can be generalised across much larger populations> increasing the validity
Weaknesses of conducting a meta-analysis
- may be prone to publication bias (file drawer problem)
- researcher may not select all the relevant studies > leaving out studies with negative or non significant results
- conclusions from meta-analysis bias as they only represent some relevant data
What value does a correlation co-efficient have to be within?
-1 and +1
What does a correlation coefficient tell us?
strength and direction of the relationship between two variables
