Data and the frequency table
Data and the frequency table
Data are answers or measurements collected to learn something.
The 24 pupils of class 6B answered the question “Which pet do you like best?”.
These are the answers, in the order they were collected:
dog, cat, dog, fish, dog, hamster, cat, dog, parrot, cat, dog, fish, cat, dog, hamster, dog, cat, fish, dog, cat, parrot, dog, hamster, cat
In a long list like this it is hard to see which pet most pupils chose.
A frequency table puts the data in order: each answer is written in it once, and beside it the number of times it came up – its frequency.
| Pet | dog | cat | fish | hamster | parrot |
|---|---|---|---|---|---|
| Frequency | 9 | 7 | 3 | 3 | 2 |
- Count with tally marks: go through the list once, and for each answer draw a stroke in its column.
- Close every five strokes with a stroke across them, so you can count in fives.
- Check: the frequencies add up to the number of data, .
From the pets’ frequency table you read at once what is hard to see in the list:
- The most frequent answer: dog, 9 pupils.
- How many more: dog against cat, – two more pupils chose a dog.
- How many pupils did not choose a dog: .
Data can be numbers too. In the frequency table they are written in order, from the smallest to the largest.
The pupils of 6B also answered the question “How many brothers and sisters do you have?”:
| Brothers and sisters | 0 | 1 | 2 | 3 | 4 |
|---|---|---|---|---|---|
| Frequency | 2 | 8 | 7 | 5 | 2 |
- 7 pupils answered 2: each of them has two brothers and sisters.
- Numbers have an order, so you can also ask “How many pupils have 2 brothers and sisters or more?”: .
The 20 pupils of class 6A chose their favourite subject.
These are the answers:
maths, PE, art, PE, science, maths, PE, English, art, PE, maths, science, PE, art, maths, PE, English, science, PE, maths
Make a frequency table.
How many pupils did not choose PE?
/ – fraction bar · Tab or the arrows – between numerator and denominator, then a note above or below · Enter – check and a new line · * – times · ^ – power, ↓ – end of the power
/ – fraction bar · Tab or the arrows – between numerator and denominator, then a note above or below · Enter – a new line · * – times · ^ – power, ↓ – end of the power
The pupils of class 6C counted how many books they read in the summer holiday:
| Books | 0 | 1 | 2 | 3 | 4 | 5 |
|---|---|---|---|---|---|---|
| Frequency | 3 | 6 | 8 | 5 | 4 | 2 |
How many pupils are there in the class?
/ – fraction bar · Tab or the arrows – between numerator and denominator, then a note above or below · Enter – check and a new line · * – times · ^ – power, ↓ – end of the power
/ – fraction bar · Tab or the arrows – between numerator and denominator, then a note above or below · Enter – a new line · * – times · ^ – power, ↓ – end of the power
How many pupils read 3 books or more?
/ – fraction bar · Tab or the arrows – between numerator and denominator, then a note above or below · Enter – check and a new line · * – times · ^ – power, ↓ – end of the power
/ – fraction bar · Tab or the arrows – between numerator and denominator, then a note above or below · Enter – a new line · * – times · ^ – power, ↓ – end of the power
How many books did the whole class read together?
/ – fraction bar · Tab or the arrows – between numerator and denominator, then a note above or below · Enter – check and a new line · * – times · ^ – power, ↓ – end of the power
/ – fraction bar · Tab or the arrows – between numerator and denominator, then a note above or below · Enter – a new line · * – times · ^ – power, ↓ – end of the power
32 pupils chose where to go on the annual school trip.
One frequency is missing from the table:
| Destination | Jerusalem | Galilee | Dead Sea | Eilat |
|---|---|---|---|---|
| Frequency | 11 | ? | 5 | 7 |
How many pupils chose the Galilee?
/ – fraction bar · Tab or the arrows – between numerator and denominator, then a note above or below · Enter – check and a new line · * – times · ^ – power, ↓ – end of the power
/ – fraction bar · Tab or the arrows – between numerator and denominator, then a note above or below · Enter – a new line · * – times · ^ – power, ↓ – end of the power
The local paper printed a table: on how many days it rained in the town in each month of last winter.
| Month | November | December | January | February | March |
|---|---|---|---|---|---|
| Rainy days | 4 | 8 | 10 | 9 | 6 |
In which month did it rain on the most days, and in which on the fewest?
On how many days did it rain in the whole winter?
/ – fraction bar · Tab or the arrows – between numerator and denominator, then a note above or below · Enter – check and a new line · * – times · ^ – power, ↓ – end of the power
/ – fraction bar · Tab or the arrows – between numerator and denominator, then a note above or below · Enter – a new line · * – times · ^ – power, ↓ – end of the power
Write a question you would like to ask your class, so that the answers are words.
Write another question, so that the answers are numbers.
Ask ten friends one of the questions, and make a frequency table of the answers.
/ – fraction bar · Tab or the arrows – between numerator and denominator, then a note above or below · Enter – check and a new line · * – times · ^ – power, ↓ – end of the power
/ – fraction bar · Tab or the arrows – between numerator and denominator, then a note above or below · Enter – a new line · * – times · ^ – power, ↓ – end of the power