To determine which distribution has the greatest spread, we need to examine their standard deviations. The standard deviation is a measure of the amount of variation or dispersion in a set of values. The higher the standard deviation, the greater the spread of the distribution.
We have the following standard deviations:
- Distribution 1: 0.2
- Distribution 2: 0.8
- Distribution 3: 1.2
- Distribution 4: 3.2
Among these values, 3.2 is the greatest standard deviation.
Thus, Distribution 4 has the greatest spread.
Therefore, the correct answer is:
```
4
```