Which graphical tool shows trends like work hours per square yard over a time period?

The choice of a Run Chart as the correct answer is appropriate because a Run Chart is specifically designed to display data points over time, allowing for the observation of trends and variations within a dataset. By plotting work hours per square yard on the vertical axis and time on the horizontal axis, a Run Chart effectively showcases how this metric changes over a specified period. This can help identify patterns, shifts, or trends that may warrant further investigation.

In contrast, other options serve different purposes: a Histogram is used to illustrate the distribution of data across different intervals, a Pareto Chart focuses on identifying the most significant factors in a dataset based on the Pareto principle, and a Flow Chart visually represents the steps in a process rather than trends over time. This distinction clarifies why the Run Chart is the most suitable choice for tracking trends such as work hours per square yard over a time period.