# research methods part 3 Flashcards

what is a co-variable

the two measured variables in a correlational analysis, the variables must be continuous

what is a continuous variable

a variable that can take on any value within a certain range

what is a correlation

determining the extent of an association between two variables, co-variables may not be linked at all (o correlation), they may increased together (positive correlation), or as one co-variable increases the other decreases (negative correlation)

what is a correlation coefficient

a number between -1 and _1, that tells us how closely the co-variables in a correlational analysis are associated

what is a curvillinear correlation

a non linear relationship between co variables

what is an intervening variable

a variables that comes between two other variables which is used to explain the association between those two variables,

what is linear correlation

a systematic relationship between co-variables that is defined by a straight line

what is a scattergram

a graphical representation of the association between two sets of scores

what is significance

a statistical term indicating that the research findings are sufficiently strong for us to accept the research hypothesis under test

what is a correlational hypothesis

This states the expected association between teh co-variables

What is a scattergram used for

- illustrates a correlation
- for each indiciaul we obtain two scores which are used to plot one dot for that individual, the co-variables determine the X and Y position

describe the correlation coefficient

- the correlation coefficient is a measure of the extent of correlation that exists between co-variables
- it is a number
- maximum value of 1
- 1 is a perfect positive correlation and -1 is a perfect negative correlation
- some correlation coefficients are written with a minus sign and some with a positive sign this shows us if the correlation is positive or negative
- the coefficient shows us how closely related the co-variables are
- then use table of significance to find out if the coefficient is strong enough

Evaluation of correlation: what is the difference between correlations and experiments

- the unique feature of an experiment is that the investigator changes the IV to effect the DV without this chnage no casual conclusions can be drawn
- in a correlation the variables are simply measured and there is no deliberate change is made, therefore no conclusion can be made about one co-variable causing the other - causal conclusion

evaluation of correlation: What are the limitations

- causal conclusions - problem because a misinterpretation of correlations may mean that people design programmes for improvement based on false premises,
- there are intervening variables that can explain why the co-variables being studied are linked
- correlation may lack internal/external validity

Evaluation of correlation: strengths

- correlations have their own special value - used to investigate trends, if correlation is significant then further investigation is justified
- if correlation is not significant then you can probably rule out a casual relationship
- can be easily repeated again so results and findings can be confirmed

what is effect size

a measure of the strength of the relationship between two variables

what is meta-analysis

a researcher looks at the findings from a number of different studies and produces a statistic to represent the overall effect

what is a review

a consideration of a number of studies that have investigated the same topic in order to reach a general conclusion about a particular hypothesis

describe what happens in a systematic review

- a review involves identifying a aim the searching for research studies that have addressed similar aims
- done by looking through various search databases which hold details of research published in academic journals
- decision is made about the search criteria, this decides what kind of study will be included or excluded for example a review of attachment might include studies that have used the strange situation and infants under one year of age

describe what happens in a meta-analysis

- technique produces an effect size as teh dependent variable in order to assess overall sides
- an example would be the 53 studies that related to the cognitive interview which demonstrated the effectiveness of the CI compared to standard interviewing techniques, the effect size is 34% which means that of all the studies the CI technique improved recall by 34% when compared to using SI interview technique

evaluation of meta-analysis

- results from a group of studies rather than just from one study can increase the validity of the conclusions drawn because they are based on a wider sample of participants
- often studies in a review produce contradictory reviews whereas a meta-analysis allows us to reach an overall conclusion by having a statistic to to represent findings of different studies
- research designs in different studies may also vary considerably which means that the studies are not truly comparable, putting them together may not always by appropriate and thus conclusions are not always valid

what should graph and tables be

- they should clearly show the findings from a study
- there should be a short but informative title
- in a graph both axes should be clearly labelled, the X axis goes across the page and is the independent variable, and the Y axis is usually frequency