Under what conditions might it be appropriate to use the mean? Median? Mode? When the median and mean are substantially different, what does that tell you about the data? What information does the range and standard deviation provide about the data?
All three measures of central tendency can be used in a normal distribution. If the mean and median differ, you probably have a skewed distribution, with the mean most influenced by the deviant scores. (Remember, the mean functions like a fulcrum [balance point].)
The measures of variability give an idea of the level of accuracy of the measures of central tendency.
