Tables and Graphs Flashcards
features of good tables
clear title
well labelled
units
notes of explanation
source of data
consistent decimal places
revenant tools and subtotals
percentage tables
convert into percent
calculate by dividing number in group by total
when to use percentage tables
when categories have different sample sizes
categorical data
add to a whole
BMI
nominal or ordinal
continuous data
time series
ratio or interval data eg height
features of bar charts (categorical)
same width
not touch
order logically
no more than 3 sets of bars
when can bars touch in a bar chart
touch in multiple bar charts if correspond to same x axis category
stacked bar charts (categorical)
categories within categories
counts or %
must add to 100 if %
pie chart (categorical)
100% = 360 degrees
convert % to proportion by divide by 100
add up to 360 degrees
limitation of pie chart
not useful for large number of categories
confusing if comparing 2 different surveys
if small number of observations, % are misleading
stem and leaf plots (continuous data)
frequency distribution more visual
no.s must be evenly placed
can identify if data concentrated around middle or skewed
stem and leaf plots structure
column to left = stem (tens)
numbers to right = leaves (digits)
stems = multiple digits, leaves have one
histogram (continuous)
only show counts or % falling in a category
joined bars
height = frequency
width = width of category
multiple categories (continuous)
categories on x
scales not misleading
start y at 0
colours for diff categories
stats in figure legend
column chart or boxplot
error bars
time series (continuous)
line graph on variable over time
time on. x
same scales when comparing
diff lines in colours
error bars / sd / se
