quantitative data management - statistics Flashcards
raw data
all of the individual data points, must be made sense of
data reduction
can add up the scores for each person, then create the mean. then see how variable the data is (how spread out) we can then answer the questions
measure of central tendency
usually the mean - an average
a single value that describes a set of data.
quasi experiments
can conclude a mean of the whole sample. useful to compare to pre-existing groups.
male v female etc
variability in scores
too see how much the lowest and highest is - how much scores vary.
variance
a large variance is a larger distance from the mean and vice versa.
we must quantify variance
calculating variance
calculate the mean, subtract from each ppt score to work out the deviation, square each deviation, add up the squared deviations of each ppt, divide squared deviation by 1 less number than ppts. square root that. = standard deviation
what does standard deviation tell us
e.g. 2.7 SD shows that most ppts recall scores where within 2.7 words above or below the mean e.g. 10
COHENS d effect size
group 1 M- group 2 M / SD pooled
small effect - 0.2
medium - 0.5
large - 0.8
big or small difference in variance.