measures of central tendency

• What is the mean?


  The most common and best measure of central tendency to use when your data distributions are continuous and symmetrical, such as when it is normally distributed.
• Data used for the mean is similar and doesn’t have any very low or high values. If it were to be plotted onto a scatter graph it would have very few gaps.
• The mean makes use of all the available data, so is the most powerful measure to use.
• The mean is good for ordinal, or interval sets of data.
• Sometimes the means end figure is a decimal, which makes it less meaningful
• The mean can generate an unrepresented figure.
• What is the median?


  It is the middle value when all the values are places in ascending (or descending) order, which can be more descriptive of the data set than the average.
• The median is the most informative measure of central tendency for skewed distributions or distributions with outliers or dealing with ordinal data.
• The median is not distorted by outliers/skewed data.
• The median doesn't consider the precise values of each observation and hense does not use all information available in the data.
• Unlike the mean, the median is not amenable to further mathematical calculation and hence is not used in many statistical tests.
• What is the mode?


  It is the most frequently occurring number that appears in the data set.
• When is the data considered bi-moral?


  When there are two (or more) modes.
• A data set can have no mode
• What is the only suitable method for looking at the frequency distribution in data?


  The mode.
• The mode is the least used and can be used when dealing with nominal data
• The mode can be located graphically unlike the mean and the median.
• The extremities in the values of the data do not affect the mode
• The mode is not defined where there are no repeats in the data set.
• Sometimes the data has one mode, or no mode at all.