statistics
help us organize data
measurements
determine potential statistics
nominal scale
no order of information. it is just name catagories.
ordinal scale
order matters. intervals aren’t necessarily the same.
interval scale
order matters. equal units of measurement. no true zero
ratio scale
order matters and has equal units. has a true zero
how can we use statistics
describe data, measure relationships, compare groups
descriptive statistics
averages, mean, mode, median
bimodal
two scores occur equally often
multimodal
three or more scores occur equally often
what does an outlier have the most effect on?
the mean
inclusive range
highest score - lowest score +1
exclusive range
highest-lowest scores
standard deviation
average distance from the mean
variance
standard deviation squared
correlation
the degree of relationship between two variables - strength
strength
the distance from zero
positive correlation
both variables increase or decrease
negative correlation
variables have an inverse relationship.
Pearson’s product-movement (Pearson’s r)
only interval and ratio data
spearman’s rho
at least one variable is ordinal
multiple correlation
correlation between multiple variables and one particular variable. single score
multiple regression
same but gives information about each predictor variable
cross-sectional design
examines differences across age groups.
