1. **State the problem:** We are asked to find the mean (average) number of online video views from the data set: 498, 327, 288, 217, 144, 445, 347, 107, 408. 2. **Formula for mean:** The mean is calculated by summing all the values and dividing by the number of values. $$\text{Mean} = \frac{\text{Sum of all values}}{\text{Number of values}}$$ 3. **Calculate the sum:** $$498 + 327 + 288 + 217 + 144 + 445 + 347 + 107 + 408 = 2781$$ 4. **Count the number of values:** There are 9 values. 5. **Calculate the mean:** $$\text{Mean} = \frac{2781}{9}$$ 6. **Simplify the fraction:** $$\frac{\cancel{2781}}{\cancel{9}} = 309$$ 7. **Interpretation:** The mean number of views is 309, which matches the given approximate mean. **Final answer:** The mean number of views is **309**.