The MEAN should only be used to summarize data that is both scaled and normally distributed. Scaled data has equal intervals like speed, weight, height, and temperature. The mean is sensitive to outliers in skewed distributions so it should only be used when the distribution is close to normal.

1. The MEAN is used when BOTH of the following
conditions are met:
(1) data is SCALED
AND
(2) distribution is NORMAL
Data with equal intervals like speed, weight,
height, temperature, etc.
Because the mean is sensitive to outliers
that are found in SKEWED distributions, you
should only use the mean when the
distribution is more or less normal.