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DataData
Data is information
Data handling is when we organise, display and try to
understand information.
Some children wanted to find out about the length of songs. They wanted to know how long most
songs were.
They listened to some songs and timed how long each one lasted
• 3min 20 seconds
• 2 min 58 seconds• 3 min 12 seconds• 1 min 59 seconds• 4 min 03 seconds• 2 min 15 seconds• 3 min 32 seconds
Here are their results:
• 3min 37 seconds
• 3 min 58 seconds• 1 min 45 seconds• 3 min 0 seconds• 3 min 13 seconds• 2 min 35 seconds• 3 min 17 seconds
Not very easy to understand is it?Not very easy to understand is it?
Let’s turn it into a graph...
Graph showing how many songs there were of each length
Length (in minutes)
Num
ber o
f son
gs
Oh dear.... That wasn’t much
help
Every song is different...
So how can we find out what sort of length is most common?
We’ll start by sorting it into a tally chart
We can group the data
Song length Number of songs
1 min 30 sec to1 min 59 sec
2 min 0 sec to 2 min 29 sec
2 min 30 sec to2 min 59 sec
3 min 0 sec to 3 min 29 sec
3 min 30 sec to3 min 59 sec
4 min 0 sec to4 min 29 sec
4 min 30 sec to4 min 59 sec
• 3min 20 seconds
• 2 min 58 seconds• 3 min 12 seconds• 1 min 59 seconds• 4 min 03 seconds• 2 min 15 seconds• 3 min 32 seconds• 3min 37 seconds
• 3 min 58 seconds• 1 min 45 seconds• 3 min 0 seconds• 3 min 13 seconds• 2 min 35 seconds• 3 min 17 seconds
Remember how we tally in fives:
So how many does this tally show?
1818
Right, let’s get back to that tally chart...
... and change it into a frequency table
Frequency tableSong length Number of songs
1 min 30 sec to1 min 59 sec
2 min 0 sec to 2 min 29 sec
2 min 30 sec to2 min 59 sec
3 min 0 sec to 3 min 29 sec
3 min 30 sec to3 min 59 sec
4 min 0 sec to4 min 29 sec
4 min 30 sec to4 min 59 sec
Song length Number of songs
1 min 30 sec to1 min 59 sec 22 min 0 sec to 2 min 29 sec 12 min 30 sec to2 min 59 sec 23 min 0 sec to 3 min 29 sec 53 min 30 sec to3 min 59 sec 34 min 0 sec to4 min 29 sec 14 min 30 sec to4 min 59 sec
Tally chart
Well, that bit was easy!
Now let’s display the information in a pictogram
We’re going to use one CD to stand for 2 songs, like this:
Song length Number of songs
1 min 30 sec to1 min 59 sec 22 min 0 sec to 2 min 29 sec 12 min 30 sec to2 min 59 sec 23 min 0 sec to 3 min 29 sec 53 min 30 sec to3 min 59 sec 34 min 0 sec to4 min 29 sec 1
Now we can use those symbols to make a pictogram
1 min 30 sec to1 min 59 sec
2 min 0 sec to 2 min 29 sec
2 min 30 sec to2 min 59 sec
3 min 0 sec to 3 min 29 sec
3 min 30 sec to3 min 59 sec
4 min 0 sec to4 min 29 sec
What else do we need?
What else do we need?
Number of songs
Song
len
gth
= 2 songs
We can show the
same information in a graph:
We can show the
same information in a graph:
Num
ber o
f son
gs
Song length
6
4
2
8Which
length of song is the
most common?
3 min to
3 min 29 sec
3 min to
3 min 29 sec
This is called the
mode
This is called the
mode
Num
ber o
f son
gs
Song length
6
4
2
8True or false?
Most songs are between
3 and 4 minutes long.
TrueTrue
Grouping dataGrouping data
When you group data, you have to make all the groups equal.
In this example, all the groups were 30 seconds long.
The same rule applies to any grouped data. If we were grouping tables test scores, we could use:
0-10, 11-20, 21-30, 31-40 and so on.
What have we learned?What have we learned?
• How to group data• How to make a tally chart• How to make a frequency table• How to make a pictogram• How to make a graph (bar chart)
• How to group data• How to make a tally chart• How to make a frequency table• How to make a pictogram• How to make a graph (bar chart)