Final answer:
The default method for summarizing data in a PivotTable is the sum of the values. The appropriate measure of center, whether it be mean, median, or mode, depends on the shape and characteristics of the data.
Step-by-step explanation:
The default method for summarizing data in a PivotTable in programs like Microsoft Excel is b) Sum. When you add a numeric field as a Value in a PivotTable, Excel will automatically calculate the sum of the values. If the data includes text, non-numeric, or blank cells, Excel may default to using the Count method.
To determine the most appropriate measure of center for a set of data, you must examine the shape of the data - whether it is skewed, has outliers, or is symmetrical. For symmetrical distributions without outliers, the mean is often used. If the data is skewed or has outliers, the median is typically better as it is not as affected by extreme values. The mode is used when the data is categorical or when the most frequently occurring value is of interest.