Answer :

To identify the mode in the given set of data, we need to follow a few key steps. Let's break the process down step-by-step for clarity.

The data set provided is:
[tex]\[ 8, 4, 10, 8, 7, 4, 8, 9 \][/tex]

### Step 1: Tally the Frequency of Each Number
First, we need to determine how many times each number appears in the data set. Below is the frequency of each number:

- The number 8 appears 3 times.
- The number 4 appears 2 times.
- The number 10 appears 1 time.
- The number 7 appears 1 time.
- The number 9 appears 1 time.

### Step 2: Create a Frequency Distribution
We can represent the frequency distribution as follows:
[tex]\[ \begin{array}{c|c} \text{Number} & \text{Frequency} \\ \hline 8 & 3 \\ 4 & 2 \\ 10 & 1 \\ 7 & 1 \\ 9 & 1 \\ \end{array} \][/tex]

### Step 3: Determine the Mode
The mode is the number that appears most frequently in the data set. From our frequency distribution:
- The number 8 has the highest frequency, which is 3.

Therefore, the mode of the data set [tex]\(\{8, 4, 10, 8, 7, 4, 8, 9\}\)[/tex] is:
[tex]\[ \boxed{8} \][/tex]