Sum of Squared Deviations Calculator

Input a dataset to calculate the sum of squared deviations instantly.

Sum of Squared Deviations Calculate

Result

What Is the Sum of Squared Deviations?

The Sum of Squared Deviations (SSD) is a measure of data dispersion. It quantifies the variability of a dataset by summing the squared differences between each data point and the dataset's mean. The formula is: \( \text{SSD} = \sum_{i=1}^{n} (x_i - \bar{x})^2 \) Where:

  • \( x_i \) represents each value in the dataset,
  • \( \bar{x} \) is the mean of the dataset,
  • \( n \) is the total number of data points.

How to Calculate the SSD

  1. Calculate the Mean: Find the average value of the dataset (\( \bar{x} \)).
  2. Compute Squared Deviations: For each data point \( x_i \), calculate the squared difference from the mean \( (x_i - \bar{x})^2 \).
  3. Sum the Results: Add all the squared deviations to get the SSD.

Example: Compute the SSD of data set [4, 8, 6, 5, 3]

Solution:

1. Calculate the Mean:

\( \bar{x} = \frac{4 + 8 + 6 + 5 + 3}{5} = 5.2 \)

2. Compute Squared Deviations:

\((4 - 5.2)^2 = 1.44\)

\((8 - 5.2)^2 = 7.84\)

\((6 - 5.2)^2 = 0.64\)

\((5 - 5.2)^2 = 0.04\)

\((3 - 5.2)^2 = 4.84\)

3. Sum the Squared Deviations:

\( 1.44 + 7.84 + 0.64 + 0.04 + 4.84 = 14.8 \)

Result: The SSD for the dataset is 14.8.