RDA Test 2 Flashcards
What is a relationship design?
Whether variables share a common relationship (i.e. as one thing increases, the other measurement either increase or decreases in response)
What is a difference design?
Whether there are differences between measurements depending on how the participants are measured
What is counterbalancing and why is it used?
Where the order of tasks/conditions for participants are altered for each participant
Used to deal with participants improving or exhibiting demand effects
What is a floor effect?
Where everyone does very poorly, or near the minimum value
What is a ceiling effect?
Where everyone does very well, or near the maximum value
What is the Hawthorne Effect?
Where participants modify their normal behaviour due to them being aware that they are being observed
What is the Clever Hans Effect?
When researchers behave in a way that can influence the participant to act in a way that is desirable for the study
What is social desirability bias?
When participants answer in a way that would be viewed more positively in terms of social norms
What is acquiescence bias?
Where a participant answering questions might agree or disagree with statements/questions without the answer being a true reflection of their feelings or opinion
What causes acquiescence bias?
Participant motivation, the set of options they can choose, all questions being phrased in the same way, etc
What should a sample be representative of?
The population of interest
What is a longitudinal study?
Where we study a behaviour or subject of interest over a longer period to time and we usually make measurements at regular intervals
What is the main reason why longitudinal studies are important?
Allows us to see how things change over time (e.g. an intervention to change a behaviour) within the same group of participants
What is a cross-sectional design study?
Where behaviour is observed over time, but instead of following one group of participants, it uses a cross-section of the population of interest and divides them into time groups
What do descriptive statistics allow us to do?
- Explore and compare our data meaningfully
- Assess any major differences between conditions/variables
- Determine the ‘shape’ of our data distributions
- Check for missing data or unusual data (e.g. an outlier)
- See how much ‘noise’ there is in our data
- Check to see whether the data are ‘fit’ to use for further statistical testing
- Look at measures of central tendency, dispersion and variation
- Organise and aggregate or disaggregate data in a meaningful way
- Get a ‘feel’ for any relevant patterns
- Present data graphically or in a tabular format
What do inferential statistics allow us to do?
- Test whether our data is normally distributed
- Determine whether differences or relationships are statistically meaningful
- Express whether we can retain or reject the null hypothesis
What are the 3 main measures of central tendency?
Mean, median, mode
What is the mean?
The average of a set of numbers, whether integers or decimals
How is the mean worked out?
Add all items in a set up, and then divide by the number or items
What is the most common measure of central tendency?
Mean
What is the median?
The middle of a set of values if you arrange them from smallest to largest
When is the median most useful?
When you have a non-normal distribution or with extreme scores, or when using ordinal data
What is the mode?
The mode is the most commonly occurring number in a set of data
When is the mode most used?
With nominal data
What do measures of variability tell us?
About the spread of data and in some instances, the amount of ‘noise’ in the data set
What are the 5 common measures of dispersion?
- Range and interquartile range
- Mean absolute deviation
- Variance
- Standard deviation
- Standard error of the mean (SE)
What is the range?
The difference between the smallest and largest value is a distribution
What is the biggest limitation regarding the range? What can be used to remedy this?
It is susceptible to an extreme score in a distribution
The interquartile range can be used to remedy this
What is the interquartile range?
When we take the centre 50% of values, between the 25th and 75th percentile
How is the interquartile range usually displayed graphically?
Box plot
What is the mean absolute deviation?
A measure of how much difference or deviation there is from the mean
How is the mean absolute deviation usually worked out?
By working out the difference between each value and the mean (ignoring all the negative signs – otherwise they would sum to zero), adding them up, and then dividing by N
What is variance?
An indication of the overall amount of variability in a set of data, but in a squared format, is used in many statistical formulae, and is denoted as s2
How is variance worked out?
By adding up the squared differences (deviations) between each value in a set of data and the mean, and then dividing by N – 1