Sum/number of items.
The mean is the average of a set of numbers. It represents the central value of the data.
Mean = Sum of all items/Number of items
Mean is a fundamental statistic used in data interpretation and problem-solving. Calculating it correctly is key for comparing data sets and solving word problems efficiently.
Middle most value.
The median is the middle value of a data set when the numbers are arranged in ascending or descending order.
If there is an odd number of items, the median is the middle number.
If there is an even number of items, the median is the average of the two middle numbers.
Median is often used to describe central tendency in data sets. It is less affected by outliers than the mean, making it important for interpreting distributions accurately.
Highest value – Lowest value in a data set.
Key Idea: Range
The range measures how spread out a data set is.
It shows the difference between the highest and lowest values.
General Rule:
Range = Highest Value−Lowest Value
A larger range means the data are more spread out; a smaller range means the data are closer together.
Why this matters for the SAT:
Range helps describe data variability in statistics questions.
Knowing how to find it quickly lets you compare data sets and understand their spread at a glance.
