Measures of Central Tendency of Data

The mean of a data set is the sum of the data divided by the number of items in the data set

The median of a set of data is the middle number of the ordered data, or the mean of the middle two numbers. The mode or the modes of the data set is the number or the numbers that occur most often

An outlier is a data value that is quite separated from the rest of the data. An outlier can be much greater or smaller than the other values in the set

An outlier greatly affects the mean of the data, so mean can never be a good representative of the data set with outlier data values

Median is the best representative of the data set when the data has outliers and there are no big gaps in the middle of the data. Mode is the best representative of the data set that has many identical numbers

The number of X's on a data value represent the frequency of that value

The mean of a data set is the sum of the data divided by the number of items in the data set

To read the ordered data set from a line plot, start from the left, write the data value corresponding to the 'X' as many times the 'X' appears above the data value

The mode or the modes of the data set is the number or numbers that occur most often

The median of a set of data is the middle number of the ordered data, or the mean of the middle two numbers

The median of a set of numbers is the middle number of the set when the numbers are arranged in order

The median divides data into two halves. The middle number of the lower half is called the first or the lower quartile

The middle number of the upper half of the data set is the third or the upper quartile

Mean = Sum of all the data values/ Number of data values

The mode of the data set is the data value that appears the maximum number of times