Measures of Central Tendency — Chapter Summary

Mean is the arithmetic average

Mean is the arithmetic average of a set of observations. For ungrouped data, the mean is the sum of observations divided by the number of observations

For grouped data

For grouped data, mean is found using the formula \(\frac{\Sigma f x}{\Sigma f}\), where f is frequency and x is the value.

This method uses an assumed mean

This method uses an assumed mean A and deviations d = x - A. The formula is \(A+\frac{\sum f d}{\sum f}\).

This method uses an assumed mean

This method uses an assumed mean A and step-deviation t. The formula is \(A+\frac{\sum f t}{\sum f} \times i\), where \(t=\frac{x-A}{f}\) in the sylla

Median is the middle value

Median is the middle value of ordered data. For raw data, if n is odd, the median is the \(\frac{n+1}{2}\) th term. If n is even, it is the average of