Frequency tables
In a nutshell
Frequency tables are used to display the quantities of different data. They are extremely useful for calculating mean, median and mode as averages of a set of data, as well as the range to determine the spread of the data.
Frequency
Definition
Frequency represents the quantity of an outcome and it answers the question, 'How many?' An outcome occurs more frequently than another if it has happened more times than the other.
Example 1
Alice flips a coin 50 times. The outcome heads has a frequency of 17. What is the frequency of tails?
The only two outcomes of a coin flip are heads and tails. Hence, as the frequencies of heads and tails sum to 50 the frequency of tails is:
50−17=33.
Tails occurs 33 times.
Table representation
When there are several different categories of the data, frequency tables can be used to display the respective frequencies of the categories. A frequency table that lists data items and shows the number of times the items occur.
Example 2
Mark creates a frequency table after asking his classmates which sport they prefer to play. His results are as follows:
Sport
| Frequency |
| Badminton | |
| Football
| |
| Hockey
| |
| Tennis
| |
Which sport is most popular?
Read the table and identify that 3 people prefer badminton, 13 people prefer football, 9 people prefer hockey and 5 people prefer tennis. The most popular sport has the highest frequency.
Football is the most popular sport.
How many classmates did Mark get data from?
Sum the frequencies of each category to find how many people Mark asked in total. Hence, Mark asked:
3+13+9+5=30 classmates
