Data and probability Flashcards
what are the 2 types of data we have
quantitative
qualitiative
what are the 4 scales of data
nominal/categorical
ordinal
ration/interval
continuous/discrete
what is ordinal data
ordered data
can interval data go into negative values
yes
what is continuous data
scale of data that has points within each points
what is discrete data
when the unit of measurement cannot be split up
what are descriptive staistics
allow you to summarise and describe the characteristics of a set of data
what 4 things do descriptive data tell us
whether there is a pattern
whether people provided different/similar scores
whether there are anomalies
whether certain scores have a high frequency that others
what are the 3 measure of central tendency
mean
mode
medium
what are the 4 measure of dispersion
range
variance
standard deviation
interquartile range
what is a low variance
mean is representable of the data as there is more similar scores
what is high variance
mean is less representable of the data
what is standard deviation
the spread of the data around the mean
what scale is probability measured on
0-1
how do we work out probability
no.of ways it can happen/total no.of outcomes
what is the gamblers fallacy
the belief that if something happens more than expected during a given period, it will happen less frequently in the future
what percentage do we accept for probability
less than 5% 0.05
what 2 things can a statistical test test?
test of relationships
test of differences
statistical test
test of relationship
tests the correlation between 2 variables
statistical test
test of differences
tests for significant differences between conditions
INFERENTIAL STATISTICS
correlation
R
pearson-parametric
spearman-non
relationship between 2 variables
INFERENTIAL STATISTICS
ANOVA
F
parametric
difference between 3+ groups
INFERENTIAL STATISTICS
t-test
T
parametric
difference between 2 groups
INFERENTIAL STATISTICS
wilcoxon
W
non-parametric
difference between 2 condtitions
INFERENTIAL STATISTICS
mann-whitney
U
non-parametric
difference between 2 groups
INFERENTIAL STATISTICS
Friedman
x2
non-parametric
difference between 3+ conditions
INFERENTIAL STATISTICS
Kruskal wallis
H
non-parametric
difference between 3+ groups
what is random sampling
every member of the population has an equal opportunity to be chosen to participate i
why do we have a sample of participants
we cant test every member of the population so we take a subset and generalise this to the entire population
what are the 4 types of sample selection
random
stratified
cluster
opportunity
what is stratified sampling
taking a sample from each group of the population according to the proportion within each group
what is cluster sampling
sampling an already selected group within the population
what is opportunistic sampling
picking the most convenient people available who were willing to take part
what are 4 things to consider when picking participants
age
gender
ethnicity
time
what are 3 measurement tools for an experiment
reaction time/accuracy
questionnaires
observations
what are 3 issues with measurements
how accurate are the tools
how do we know what the participants true score is
every time we measure something, we also measure some degree of error
what are the 2 degrees of error
systematic error
random error
what is a systematic error
caused by equipment
what is a random error
caused by anything else e.g. boredom
what are 3 ways we can minimise error
take good measurements
minimise distractions for participants
test your procedure
