Which of the following scatterplots best shows an outlier in only the $x$-direction?

• A. A scatterplot where all points are clustered along a straight line except for one point that is far above the line.
• B. A scatterplot where all points are tightly clustered with no apparent outliers.
• C. A scatterplot where all points are clustered along a straight line except for one point that is far to the right but at the same vertical level as the others.
• D. A scatterplot where all points are evenly spread out in a circular pattern.

Answer: (C)

Verified step by step guidance

1. Understand what an outlier in the x-direction means: it is a data point whose x-value is significantly different from the other x-values, while its y-value is similar to the rest.
2. Examine each scatterplot description to identify where the unusual point lies relative to the x-axis and y-axis.
3. For the first option, the outlier is far above the line, meaning the y-value is unusual, so this is an outlier in the y-direction, not x-direction.
4. The second option describes no outliers, so it cannot show an outlier in any direction.
5. The third option describes a point far to the right but at the same vertical level, meaning the x-value is unusual but the y-value is typical, which matches an outlier in the x-direction.