To estimate the center and spread of the daily number of birds rescued coated with oil during the BP oil spill, the researcher would typically use a box plot (box-and-whisker plot) or a histogram :

• Box plot : This graph visually displays the median (a measure of center), quartiles, and potential outliers, giving a clear summary of the data's center and spread (interquartile range). It is especially useful if the data may be skewed or contain extreme values.
• Histogram : This graph shows the frequency distribution of the daily counts, allowing the researcher to observe the shape, center (mean or mode), and spread (variability) of the data.

Both graphs help quantify and visualize the typical number of birds rescued each day and how much daily counts vary

. For example, the box plot’s median line represents the center, and the length of the box indicates the spread of the middle 50% of data (IQR), while the whiskers show the overall range. The histogram shows how often different rescue counts occur, helping to identify the mode and spread visually. Therefore, a box plot would be the most straightforward choice to estimate center and spread numerically and visually from the daily rescue counts.