Humans aren't the only animals that get cancer, other organisms get tumors as well and their risk may be influenced by environmental factors. An ecologist decides to study whether pollution in lakes causes cancer so he collects 100 fish from each of two lakes, one known to be polluted and the other known to be pristine. He then dissects them and determines if they have tumors in their tissues or not. His data is shown below.

$\begin{array}{|l|l|l|}
\hline & \text { Polluted } & \text { Pristine } \
\hline \text { Tumors present } & 26 & 15 \
\hline \text { No tumors } & 74 & 85 \
\hline
\end{array}$
-What proportion of all fish have tumors?

Question

Humans aren't the only animals that get cancer, other organisms get tumors as well and their risk may be influenced by environmental factors. An ecologist decides to study whether pollution in lakes causes cancer so he collects 100 fish from each of two lakes, one known to be polluted and the other known to be pristine. He then dissects them and determines if they have tumors in their tissues or not. His data is shown below.
​
 $\begin{array}{|l|l|l|}
\hline & \text { Polluted } & \text { Pristine } \
\hline \text { Tumors present } & 26 & 15 \
\hline \text { No tumors } & 74 & 85 \
\hline
\end{array}$
-What proportion of all fish have tumors?

Quizplus · Accepted Answer

The total number of fish with tumors is 26 (from the polluted lake) + 15 (from the pristine lake) = 41. The total number of fish is 200 (100 from each lake). The proportion of fish with tumors is 41/200 = 0.205, or 20.5%, which rounds to 20%.

Humans Aren't the Only Animals That Get Cancer, Other Organisms