How to Calculate the Geometric Mean

The Geometric Mean of a data set  is given by:

NB: The geometric mean of a data set is less than the data set's arithmetic mean unless all members of the data set are equal, in which case the geometric and arithmetic means are equal.

Worked Example

A maths tutor observed that during the last academic year a student increased his score by 20% in the first semester, 30% in the second semester and 50% in the third semester. What is the average increase in the performance of the student?

Solution 1

Arithmetic Mean

Solution 2

Geometric Mean

Profile

Emmanuel Ofori Amanfo is a Mathematician and an Entrepreneur with interest in Statistics, Finance, Economics, IT, Econometrics and Law.

He holds a Bachelor of Science degree in Mathematics from Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.

Emmanuel Ofori Amanfo’s intellectual interest is about using mathematics to model and solve real world problems.  After graduating from the university in June 2010, he worked as a census enumerator for the Ghana Statistical Service during the 2010 Ghana Population and Housing Census.

In addition he worked as a Polling Assistant for the Electoral Commission of Ghana during the 2010 District Assembly and Unit Committee Elections.

Though a Mathematician, his science background enabled him teach science during his national service in October 2010 – August 2011 at the junior high school level under the Ghana Education Service.

He had an internship from October 2011 – September 2012 as a Customer Service Officer and Data Entry Clerk with Okomfo Anokye Rural Bank Ltd in Wiamoase, Ghana.

He has been teaching mathematics since October 2012 at Osei Tutu Senior High School in Akropong-Ashanti, Ghana.