A study was done on the weights of different types of fish in a pond. A random sample of fish were caught and marked in order to ensure that none were weighed more than once. The sample contained 150 largemouth bass, of which 30% weighed more than 2 pounds. Which of the following conclusions is best supported by the sample data?

Options

A. The majority of all fish in the pond weigh less than 2 pounds.
B. The average weight of all fish in the pond is approximately 2 pounds.
C. Approximately 30% of all fish in the pond weigh more than 2 pounds.
D. Approximately 30% of all largemouth bass in the pond weigh more than 2 pounds.

Explanation

To solve the problem, we need to analyze the information provided about the sample of fish and determine which conclusion is best supported by the data.

### Step 1: Understand the sample data
The sample consists of 150 largemouth bass, and we know that 30% of these fish weigh more than 2 pounds.

**Calculation:**
- Total number of largemouth bass = 150
- Percentage that weigh more than 2 pounds = 30%

To find the number of largemouth bass that weigh more than 2 pounds:
\[ \text{Number of bass weighing more than 2 pounds} = 30\% \text{ of } 150 = \frac{30}{100} \times 150 = 45 \]

### Step 2: Analyze the conclusions
Now, we need to evaluate the provided conclusions based on the sample data.

1. **Conclusion A**: The majority of all fish in the pond weigh less than two pounds.
- We cannot conclude this since we only have data about largemouth bass, not all fish in the pond.

2. **Conclusion B**: The average weight of all the fishes in the pond is approximately two pounds.
- This cannot be determined from the sample data as we do not have information about the average weight.

3. **Conclusion C**: Approximately 30 percent of all fish in the pond weigh more than two pounds.
- This is misleading because the 30% refers only to the largemouth bass, not all fish in the pond.

4. **Conclusion D**: Approximately 30 percent of largemouth bass in the pond weigh more than two pounds.
- This conclusion is directly supported by the sample data, as we calculated that 45 out of 150 largemouth bass weigh more than 2 pounds, which is indeed 30%.

### Final Conclusion
The best-supported conclusion based on the sample data is:
**Conclusion D**: Approximately 30 percent of largemouth bass in the pond weigh more than two pounds.