Psychology - Research methods - Factors affeting choice of statistical tests Flashcards
What do Descriptive statistics do?
Give summaries of data that we have collected from our research and an indication of what the statistical analysis may reveal. Levels of measurements are used.
Levels of measurement
Used to try to categorise our data into one of four types so we can select the most appropriate statistical test to analyse results.
What are the levels of measurements?
Nominal, Ordinal, Interval
Nominal level of measurement
Data consists of the numbers of participants that might fall into different categories and a person can be placed in one category only.
Ordinal levels of measurements
Data can be placed in rank order from lowest to highest. ordinal scale can consist of measurements that are of unequal intervals.
Interval level of measurements
Data has fixed and even intervals. units are fixed.
What are the main 7 statistical tests?
Chi squared, Spearman’s rho, Mann Whitney, Wilcoxon, Pearson r, Related t-test, Unrelated T-test
Which of the statistical tests are non parametric?
Chi Squared, Spearman’s Rho, Mann Whitney, Wilcoxon
Which of the statistical tests are parametric?
Pearsons R, Related t-test, Unrelated t-test
Which of the statistical tests are used for a test of difference?
Chi squared, Mann Whitney, Wilcoxon, Related t-test, Unrelated t-test
Which of the statistical tests are used for correlations?
Spearman’s Rho, Pearsons R
Which of the statistical tests are used for associations?
Chi squared
What is the difference between Parametric tests and non-parametric tests?
Parametric tests are more robust and rely on actual data rather than examining rank order so will more likely detect if the data is significant or not.
What are the three factors that mean a parametric test can be conducted?
Interval level of measurements, normal distribution, Variance of dataset
Interval level of measurement
Data must be interval rather than ordinal
Normal distribution
The data collected should be taken from a population that shows a normal distribution curve rather than skewed
Variance of data
The data should have similar variance or spread of scores and can be examined by looking at the dispersion of sara and standard deviation
How to decide what tests to use? (three questions)
1) Is it looking at correlations, test of difference or an association? 2) Which research design is being used 3) which level of measurement is being used in
If you are using a correlation what statistical test should you use?
Spearman’s Rho or Pearson’s r
If you are looking for a test of difference then what statistical test should you use?
Mann Whitney, Chi Squared, Wilcoxon, Unrelated t-test or Related t-test
If looking for an association between variables then what statistical test would you use?
Chi Squared
What are the types of research designs used?
Independent measures, repeated measures or matched pairs design
