1. **Stating the problem:** We are given a list of numbers and asked to find the sum, mode, mean, and median of the data set. 2. **Sum:** The sum is the total of all numbers added together. 3. **Mode:** The mode is the number that appears most frequently in the data set. 4. **Mean:** The mean (average) is calculated by dividing the sum of all numbers by the count of numbers. 5. **Median:** The median is the middle value when the numbers are arranged in ascending order. If there is an even number of values, the median is the average of the two middle numbers. 6. **Calculations:** - Count the numbers: $n = 80$ - Sum all numbers: $\text{sum} = 408.68$ - Mean: $$\text{mean} = \frac{\text{sum}}{n} = \frac{408.68}{80} = 5.1085$$ 7. **Mode:** The number 5.000 appears most frequently (7 times). 8. **Median:** Sort the numbers and find the middle two values (40th and 41st): both are approximately 5.002 and 5.003 (average about 5.0025). **Final answers:** - Sum = 408.68 - Mode = 5.000 - Mean = 5.1085 - Median = 5.0025