L5 Data visualisation Flashcards
everything we measure carries a what?
element of uncertainty
how do we account for random error?
reporting results with a margin of error
what war was Florence Nightingale in?
Crimean
what did Florence Nightingale do from July 1854 to end of 1855?
document:
- how many soldiers died
- what month they died in
- cause of death
when was FN’s work published?
1858
what did FN created? and what did this do?
visualisations of her data to send back to London
- was effective as allowed British army to see where deaths were preventable and where to allocate resources
standard bar charts display -
categorical data clearly
if a bar chart is not shown as a percentage when what does it not need to do?
= 100
what are bar charts good for?
comparing the size of groups
what is the difference in a cluster bar chart?
each year has a cluster of bars
what is a cluster bar chart good at?
showing patterns
are 3D bar charts good / should we use them?
no
why are 3D bar charts so bad?
- look bad
- difficult to interpret
- difficult to directly compare the height of bars
when are graphs more beneficial than tables?
when there is lots of information points and data
- i.e. different factors (years / places / etc.)
what did Hans Rosling do?
help develop stats to do with health
- showed Govs. where to put money and resources
do statistics prove things? what do they do?
no
- they help us understand how uncertain we should be about a measurement
pie charts purpose = to
illustrate proportions
pie charts show -
relative size of categories that add up to 100%
who dislikes pie charts?
data scientists
why do data scientists dislike pie charts?
as they take up a lot of space
what can sometimes just show info better than pie charts?
tables
histograms are normally used to display -
continuous numerical data
what are histograms give us quickly?
an overview of the spread of data
with histograms what are we interested in that’s different to bar charts?
the size of each bin - not height
data is right skewed when is it….
bigger than median
what are density plots similar to?
histograms
draw what a density plot looks like:
.
density plots are a what?
smoothed out version of a histogram
what are density plots as if you did?
drew a freehand line over a histogram
what does histograms show?
the distribution of a continuous variable
box plots = a
standardised way of displaying the distribution of data on a five number summary
what are box plots sometimes known as?
whisper plots