Date post: | 23-Jan-2018 |
Category: |
Education |
Upload: | safwan-brightwell |
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WHICH GRAPHIC TO USEHow to Choose
there are three main types of graphic
bar chart pie chart line graph
all three are used to display different kinds of data
let’s have a look at some examples
using a class of 30 students
and information about their social media use
BAR CHARTS
bar charts are good for showing discrete categories
of data
let’s say we wanted to find out which social media apps
they use
so we ask them to answer a survey telling us which apps
they use
it should give us a table that looks like this
Snapchat 19
Twitter 21
Instagram 17
Facebook 12
Other 11
as the total is more than 30, we can see that most of them
use more than one app
Snapchat 19
Twitter 21
Instagram 17
Facebook 12
Other 11Total = 80
if we add all the responses together, we get more than 100%
this means the people who use each app are a discrete group
if the number of people using one app increases, it doesn’t mean the number of people using other apps goes down
Snapchat 26
Twitter 21
Instagram 17
Facebook 12
Other 11
because we want to compare how may people use each app
we need to display the information in a bar chart
0
10
20
30
Snapchat Twitter Instagram Facebook Other
PIE CHARTS
pie charts are good when we want to show parts of a whole
now, let’s say we wanted to find out which app they use
the most
so we ask them to answer another survey, telling us their
favorite app
we should get a table that looks like this
Snapchat 9
Twitter 14
Instagram 3
Facebook 2
Other 2
this time, because each person only selected one app, we have a closed group of 30 responses
so when we add the different subgroups together, we get 100%
this means we can consider each subgroup a percentage of
the whole class
so we need to display the information in a pie chart
7%7%
10%
30%
47%
TwitterSnapchatInstagramFacebookOther
LINE GRAPHS
line graphs are used to show how things change
usually over time
the surveys we’ve done so far don’t show us any kind of change
but let’s say we wanted to see how the results changed
we could do one of the same surveys repeatedly
so let’s say we ask them to answer the survey about their
favorite app
and we ask them at the beginning of every year
we’d get a table that looks like this
2014 2015 2016 2017
Snapchat 2 3 3 9
Twitter 10 14 19 16
Instagram 4 5 3 3
Facebook 14 8 5 2
now we can see that people’s favorite app has changed over time
and we can show this with line graph
0
5
10
15
20
2015 2016 2017 July
Snapchat Twitter Instagram Facebook
so all three kinds of chart show different kinds of data
bar chart pie chart line graph
discrete groups
parts within a whole
change over time
now you know which one to use
END