How to Calculate Mean for Sample Population

News outlets regularly report statistics such as "the average American spends 18 percent of their budget on transportation." No one surveyed every U.S. resident to come up with this number; statistics for large populations rely on data collected from a sample population. In properly constructed research, the mean of a sample population provides an accurate estimate of the mean for the entire population. The letter "X" with a horizontal bar over the top indicates a sample mean.

Instructions

1. Add together the numerical values for all members of the sample population.

2. Divide the sum by the number of members in the population to get the mean.

3. Record the result using "Xbar =" to indicate the mean is for a sample population.

References

• Children's Mercy Hospitals and Clinics; What Is a Mean?; Steve Simon; July 2008
• Missouri State University; Introductory Statistics: Concepts, Models and Applications; David Stockburger; 1996
• "New York Times"; All of Inflation's Little Parts; May 3, 2008