Chi Square Flashcards
What are descriptive statistics?
stats that describe and summarise a set of data
measures of central tendency: mean, mode, median
measures of dispersion: variance. standard deviation, range
When can Chi Squared be used?
Nominal data
Frequency counts
If there is more than 3 variables, more tests are needed
Describes a correlational relationship
Independent groups
What does Chi squared measure?
Tests whether the frequency counts in the nominal categories occur by chance or if there’s a relationship
X2= chi squared symbol
What’s a critical value?
Either end of a bell curve
If the statistic falls outside of the critical value, then the hypothesis can be rejected
Accepting null hypothesis
What are inferential tests?
stats that help us to predict population characteristics from the sample characteristics
e.g. estimating population parameters: sd, confidence intervals
and hypothesis testing
What are parametric and non-parametric data?
parametric: data that represents normal distribution and numerical data
non parametric: non-normally distributed and can be ordinal or nominal
What is a crosstabulation table? What is a cell?
Column frequencies and row frequencies
Each frequency count is called a cell
What do es this X2 (1, N= 217) = 59.04, P < .05 mean in R studio?
X2= chi squared
1= degrees of freedom
59.04 is the result
p < .05 is the significance level
What are the degrees of freedom? How is it calculated?
calculating: total number of participants - 1
numbers of scores in a given set are fee to vary
critical value depends on the degree of freedom
How do we calculate the degrees of freedom in chi squared?
number of rows - 1 X number of columns - 1
When is the McNemar test used?
Used for paired nominal data rather than independent like in Chi Squared
Two sets of frequency tables for participants
Testing participants before and after the study
