If the mean of 12 observations is 9, find the sum of the 12 observations.

Answer

To find the sum of the 12 observations when the mean is given, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the formula for Mean**:
The mean (average) is calculated using the formula:
\[ \text{Mean} = \frac{\text{Sum of all observations}}{\text{Number of observations}} \]

2. **Identify the given values**:
From the question, we know:
- Mean = 9
- Number of observations = 12

3. **Set up the equation**:
We can rearrange the mean formula to find the sum of observations:
\[ \text{Sum of all observations} = \text{Mean} \times \text{Number of observations} \]

4. **Substitute the known values**:
Now, substitute the values we have into the equation:
\[ \text{Sum of all observations} = 9 \times 12 \]

5. **Calculate the sum**:
Now, perform the multiplication:
\[ 9 \times 12 = 108 \]

6. **Conclusion**:
Therefore, the sum of the 12 observations is:
\[ \text{Sum} = 108 \]

### Final Answer:
The sum of the 12 observations is **108**.

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