Skill: Interpret data sets

A data set is a collection of information. A table often shows:

• Categories: what is being counted
• Frequencies: how many are in each category

When interpreting a data set, read the labels carefully and use the numbers to compare categories or find totals.

Example: A class surveys students about their favorite pets.

Favorite pet	Number of students
Dog	9
Cat	6
Fish	4
Bird	2

Step 1: Identify what each number means.
The number $9$ means 9 students chose dogs. It is the frequency for dogs. The number $2$ means 2 students chose birds.

Step 2: Find the greatest and least frequencies.
The greatest number is $9$, so dogs were the most popular choice.
The least number is $2$, so birds were the least popular choice.

Step 3: Find the difference between two categories.
To find how many more students chose dogs than fish, subtract:

$$9-4=5$$

So, 5 more students chose dogs than fish.

Step 4: Find the total number of students.
Add all the frequencies:

$$9+6+4+2=21$$

So, 21 students answered the survey.

Remember: the category tells what is being counted, and the frequency tells how many. Use the frequencies to compare categories, find differences, and calculate totals.