Alpha Value
defines the probability that the null hypothesis will be rejected, typically 5%
Alternative Hypothesis
states there is a relationship between two variables being studied
ANOVA
Analysis of Variance
tests whether there are statistically significant differences between the means of 3 or more samples
One-Way ANOVA
used with independent groups
Factorial ANOVA
used with multiple independent groups
ANCOVA
an ANOVA that includes a control variable
MANOVA
an ANOVA with multiple dependent variables
A Priori Test
a version of post-hoc test carried out before the ANOVA, data-driven
Beta
how much one variable changes as another changes, demonstrated by a slope of best fit
Bimodality
distribution with two peaks, generally indicates two groups within a dataset
Bin Size
categories for continuous data in a histogram to be organised into
Bivariate Data
data involving two variables, eg how tall and heavy they are
Bonferroni Correction
form of a priori test, involves adjusting the alpha level for our rejection of the null hypothesis with the new alpha level being based on the number of comparisons, then evaluate any p values from the T test against the new alpha cut off; alternatively, you an adjust the p-value
Categorical/Nominal Data
where data items exist as one of a number of unrelated options, eg participants select their answer from options red, yellow and green; these cannot have a mean or median, but can have a mode
Central Limit Theorem
states that under appropriate conditions, the distribution of a normalised version of the sample mean converges to a standard normal distribution; this holds even if the original variables themselves aren’t normally distributed
Central Tendency
ways of measuring the centralness of data
Mean
add up all data items and divide by the number of data items
Median
middle number in the data set
Mode
the value that happens the most
Confidence Interval
a range of values likely to include the population value with a degree of confidence, express how accurate an estimation of the a population parameter will be, normally indicated as a percentage where the population mean lies between an upper and lower bound
Continuous/Interval Data
where potential data items go in a specific order with a fixed gap in between; mean, median and mode are all possible
Correlations
quantify relationships by showing how much of a relationship there
Correlation Coefficient
size of the effect, gives an indication of effect size
Curvilinear Relationship
as one variable changes, so does the other but only up to a certain point, after which there’s either no relationship or the direction of the relationship changes