descriptive statistics Flashcards
what do descriptive statistics allow us to do
make initial sense of data
present it meaningfully to others
frequency distributions
examine values by ordering from lowest to highest, groupng the same values together
histogram
used for ordinal data
values grouped into bins
box plots
show minimum and maximum values and middle 50% of values
used for ordinal data
measures of central tendency
where on the frequency distribution values tend to centre or cluster together
mode
most frequent value
median
central or middle value when arranged in numerical order
mean
the average of all values in the dataset
dispersion
the spread of variability of values in the frequency distribution
the range
distance between lowest and highest values
standard deviation and variance
measures of dispersion around the mean
bar charts
used as frequency distributions
display means and percentages
line charts
used to show change from one condition to another over a period of time
normal distribution
symmetrical around midpoint
mode median and mean are the same
positively skewed
mean>median>mode
