Choosing Appropriate Measures of Center
Choosing appropriate measures of center is a Grade 6 statistics skill in Big Ideas Math Advanced 1, Chapter 9: Statistical Measures. Students learn when to use the mean (best for symmetric data without outliers) versus the median (better when outliers are present or data is skewed) as the most representative measure of a data set.
Key Concepts
The choice of which measure of center to use depends on the type of data and the distribution shape. For numerical data that is roughly symmetric, both mean and median work well. For skewed numerical data or data with outliers, the median is typically more representative of the center. For categorical data or when finding the most frequent value is important, the mode is the appropriate choice.
Common Questions
When should you use the mean instead of the median?
Use the mean when data is roughly symmetric and has no significant outliers. The mean works well when all values contribute equally to representing the typical value of the data set.
When is the median a better measure of center than the mean?
The median is better when data contains outliers or is skewed, because the median is not affected by extreme values. For example, if one student scored 98 and everyone else scored around 60, the median better represents the typical performance.
What are the mean, median, and mode?
The mean is the arithmetic average (sum divided by count), the median is the middle value when data is ordered, and the mode is the value that appears most often. All three are measures of center.
Where is this skill taught in Big Ideas Math Advanced 1?
Choosing appropriate measures of center is covered in Chapter 9: Statistical Measures of Big Ideas Math Advanced 1, the Grade 6 math textbook.