Learn How to Calculate Trimmed Mean - Tutorial

Definition

Trimmed Mean is an averaging method which eliminates a partial percentage of the greatest and smallest values before evaluating the standard mean of the given data.

Example :

Calculate the 20% trimmed mean for the number set {8, 3, 7, 1, 3, 9}

Given,

Trimmed Mean Percent = 20/100 = 0.2 Sample Size=6

To Find,

Trimmed Mean Value

Solution:

Step 1:

Let us first calculate the value of Trimmed count (g), where g refers to number of values to be trimmed from the given series. g = Floor(Trimmed Mean Percent x Sample Size) g = Floor(0.2 x 6) g = Floor(1.2) Trimmed count (g) = 1

Step 2:

Write down the given set of numbers {8, 3, 7, 1, 3, 9} in ascending order, = 1, 3, 3,7,8,9 As the trimmed count is 1, we should remove one number from the beginning and end. So, we remove first number(1) and last number(9) from the above set of numbers, = 3, 3, 7, 8

Step 3:

Now, calculate the Trimmed Mean denoted as μ μ = ∑ X_i / n μ = (Sum of your Trimmed Set / Total Numbers in Trimmed set) μ = (3 + 3 + 7 + 8 ) / 4 μ = 21 / 4 μ = 5.25 Hence the value of Trimmed Mean =5.25