Research Methods Flashcards
What are the 6 rules of thumb for constructing questionnaires
Make items clear (unambiguous) Avoid presuming questions Use simple language - short items are best Avoid double-barrelled Qs Avoid double negatives Avoid v mild or extreme Qs
What are the advantages / disadvantages of using a Visual Analogue Scale
Advantage: Very sensitive - useful for measuring before + after responses
- Difficult for ps to remember previous responses
Disadvantage: False precision - how meaningful are the small differences along the scale
What are the advantages / disadvantages of using a 0-100 scale
Disadvantage: Ps may respond in multiples of 5 / 10, reducing the number of options
- False precision: how meaningful is a difference of 2 digits
What are the advantages / disadvantages of using worded response categories (not helpful - very helpful)
Alternative?
Disadvantages: Difficult to assess where the points lie in the psychological continuum / interval between categories- points may not be equal
Alternative: Likert
What is Thurstone Scaling and what are advantages / disadvantages
Present statements, some of which show favouritism for one variable / another
Get around 50 judges to rate the items
Advtanges: Easy for ps to indicate agreement, not strength
Easy to develop alternate forms of the scale
Disadvantages: V labour intensive - need 50 judges
- Judges’ ratings may be different from potential ps’
What is skewness a measure of
Skewness is a measure of symmetry (indicates an issue with the items - too many low / high answers)
What is kurtosis a measure of
Kurtosis is a measure of flatness of distributions
What are z scores
Z scores / standard scores indicate the number of SD away from the mean a data point is
Skewness statistic / Std. Error
Kurtosis statistic / Std. Error
What must the z score be greater than to indicate a problem
If the z score is greater than 3.08, this indicates there is significant skewness / kurtosis and the item should be removed
What is the definition of a correlation
The degree to which 2 variables co-relate
What is the definition of correlation coefficient
An index of the extent to which two variables are linearly correlated (strength of linear relationship)
What are the assumptions of Pearson’s Correlation Coefficient and how does it measure scores
Pearson’s correlation uses the size of the scores to measure
- Variables must be measured using interval data
- Variables must be linearly related
Report Pearson’s Correlation Coefficient
There was a sig / non-sig pos / neg correlation between x and y r(df) r = , p = . Description of correlation
How does Spearman’s Rank Correlation Coefficient measure data and what are the assumptions it has
Spearman’s ranks the scores and correlates the ranks
- A monotonic, but non-linear scatterplot
- Ordinal data (categories)
- When outliers are present
What are monotonic relationships
When variables move in the same direction but not necessarily at a constant rate
Report Spearman’s Correlation Coefficient
Due to the presence of outliers / monotonic relationship / ordinal data - strength was measured using Spearman’s Rank Correlation Coefficient
Sig / non-sig pos / neg correlation r(df) r = , p = . Such that…
When is a Partial Correlation used and what does it measure
Partial Correlation is used to control for a third variable
It measures the strength + direction of linear relationship between two variables when controlling for the effect of a third variable
Takes out the amount of variance explained by the variable
What should you do with participants’ data
Make the questionnaires anonymous
Use participant codes
Store names separately from data
Keep consent forms in a locked drawer
When should deception be used / how
Avoid deception if possible
If deception is necessary, give a full debrief of the true aims
What is a Regression analysis used for and how does it do this
Regression analysis tests how well a set of IVs are able to predict a DV
Can test the model as a whole (R₂) overall variance %
Or the the independent contribution of each IV (B) beta weights
What are unstandardised coefficients and standardised coefficients (beta weights) a measure of
Regression coefficient: amount of change occuring in DV for one unit change in IV with effect of other IVs partialled out (unique contribution)
Beta weights are a standardized measure of the slope converted into SD. For every 1 SD increase in IV, the DV will go up (beta weight)
what is the equation for Regression analysis and what does it mean?
Y’ = a + bX
a is the intercept in Y axis, when x = 0
b is the slope (amount of change in y for one unit increase in X)
X = score on the variable x
Report a multiple regression analysis (4 stages)
A multiple regression analysis was performed with .. as IV and .. as DV
Regression was sig / not sig, F(df, residual) = F score, p = .
Explained r2 % of the variance in the IV
Inspection of the beta weights revealed that IVs made a sig / not sig independent contribution to prediction of DV
How do you report significant beta weights
One star for less than 0.5 [* p < 0.5]
Two stars for less than 0.1 [** p < 0.1]
Three stars for less than 0.01 [*** p < 0.01]