Question

(b) an environmental study was conducted. it reported that houses with more inhabitants do not necessarily produce more or less trash. what can be determined?
there is no correlation between number of inhabitants and amount of trash produced.
there is a correlation between number of inhabitants and amount of trash produced. however, there is no causation. this is because there is probably an increase in the amount of trash produced with an increase in the number of inhabitants.
there is a correlation between number of inhabitants and amount of trash produced. there may or may not be causation. further studies would have to be done to determine this.

Explanation:

Correlation measures the relationship between two variables. A positive correlation means as one variable increases, the other also tends to increase. Causation implies that one variable directly causes the change in the other. Just because there is a correlation (more inhabitants and more trash) doesn't mean there is causation (inhabitants directly causing trash amount - other factors could be at play like consumption habits etc.).

Answer:

There is a correlation between number of inhabitants and amount of trash produced. However, there is no causation. This is because there is probably an increase in the amount of trash produced with an increase in the number of inhabitants. There may or may not be causation. Further studies would have to be done to determine this.