Answered

The following table shows hypothetical data for two experimental treatments (Treatment A and Treatment B) against two stages of cancer (Early and Advanced). "Remission" indicates a successful treatment. "Rate" is the proportion of remissions.

\begin{tabular}{|l|r|r|r|r|r|r|}
\hline & \multicolumn{3}{|c|}{ Early } & \multicolumn{3}{|c|}{ Advanced } \\
\cline { 2 - 7 } Treatment & Remissions & Death & Rate & Remissions & Death & Rate \\
\hline A & 5 & 1 & 0.833 & 4 & 6 & 0.400 \\
\hline B & 10 & 4 & 0.714 & 1 & 4 & 0.200 \\
\hline
\end{tabular}

This table shows the same data aggregated into a two-way table.

\begin{tabular}{|l|r|r|r|}
\hline Treatment & Remissions & Deaths & Rate \\
\hline A & 9 & 7 & 0.563 \\
\hline B & 11 & 8 & 0.579 \\
\hline
\end{tabular}

Which is true for this scenario?



Answer :

Let's analyze the given data for both the early stage and advanced stage treatments and then look at the aggregated data, step-by-step.

### 1. Early Stage Data Analysis
For the early stage treatment:

- Treatment A:
- Remissions: 5
- Deaths: 1
- Rate ([tex]\( \text{Remissions} / (\text{Remissions} + \text{Deaths}) \)[/tex]): 0.833

- Treatment B:
- Remissions: 10
- Deaths: 4
- Rate: 0.714

### 2. Advanced Stage Data Analysis
For the advanced stage treatment:

- Treatment A:
- Remissions: 4
- Deaths: 6
- Rate: 0.400

- Treatment B:
- Remissions: 1
- Deaths: 4
- Rate: 0.200

### 3. Aggregated Data Analysis
For the aggregated treatments data:

- Treatment A:
- Remissions: 9
- Deaths: 7
- Rate: 0.563

- Treatment B:
- Remissions: 11
- Deaths: 8
- Rate: 0.579

### Conclusion:
- When we look at the early stage, Treatment A has a higher rate of remission (0.833) compared to Treatment B (0.714).
- For the advanced stage, Treatment A again has a higher rate of remission (0.400) compared to Treatment B (0.200).
- However, when we look at the aggregated data, Treatment B has a slightly higher overall remission rate (0.579) compared to Treatment A (0.563).

This scenario is an example of Simpson's Paradox, where treatment B appears to be better when aggregated, even though treatment A appears better in each individual stage (early and advanced).

Thus, the true statement for this scenario is an illustration of Simpson's Paradox.