Merits:

• It is rigidly defined.
• It is easy to calculate and simple to follow.
• It is based on all the abservations.
• It is determined for almost every kind of data.
• It is finite and not indefinite.
• It is readily put to algebraic treatment.
• It is least affected by fluctuations of sampling.

Demerits:

• The arithmetic mean is highly affected by extreme values.
• It cannot average the ratios and precentages properly.
• It is not an approprite average for highly skewed distributions.
• It cannot be computed accurately if any item is missing.
• The mean sometimes does not coincide with any of the abserved value.