Based on your description of the scatterplot, here are the characteristics identified:
- The dot at 0.5 hours studied and 45 test grade could potentially be an outlier since it's somewhat isolated and significantly lower than the cluster of data points at higher hours studied (between 1 to 4.5 hours).
- The cluster observed is formed by the data points between 1 to 4.5 hours studied and test grades ranging from 77 to 98.
Therefore, the best response would be: There is one cluster and one outlier.