Find the absolute change and the relative change in the following case.
The estimated number of refugees in a part of the world increased from 7.8 million in 2005 to 11.3 million in 2020 .
The absolute change is $\square$ million
(Simplify your answer. Type an integer or a decimal.)

Step 1 ：The estimated number of refugees in a part of the world increased from 7.8 million in 2005 to 11.3 million in 2020.

Step 2 ：The absolute change is the difference between the final value and the initial value.

Step 3 ：In this case, the absolute change in the number of refugees from 2005 to 2020 is the difference between 11.3 million and 7.8 million.

Step 4 ：Let's denote the initial value as \(initial\_value = 7.8\) and the final value as \(final\_value = 11.3\).

Step 5 ：Then, the absolute change can be calculated as \(absolute\_change = final\_value - initial\_value\).

Step 6 ：Substituting the given values, we get \(absolute\_change = 11.3 - 7.8 = 3.5\).

Step 7 ：Final Answer: The absolute change is \(\boxed{3.5}\) million.