The formula to calculate the Dominance Index (DI) is:
\[ DI = \left(\frac{S}{T}\right) \times 100 \]
Where:
Let's say the number of species in the sample (S) is 50, and the total number of species in the population (T) is 200. Using the formula:
\[ DI = \left(\frac{50}{200}\right) \times 100 \]
We get:
\[ DI = 25\% \]
So, the Dominance Index is 25%.