Final answer:
Callie has organized her data into a frequency distribution, which is depicted by a histogram showing the number of observations in each income category.
Step-by-step explanation:
Callie has created a frequency distribution by arranging her gathered data on the working conditions and stress levels of domestic workers, including their annual income, from low to high and noting how many workers fall within each category using a histogram.
When data is organized in such a manner, it allows us to clearly see the number of observations (frequency) within a series of intervals, helping us to understand how the data is distributed across different levels of income. The purpose of such a representation is to summarize the data set by showing the number of observations that occur in each category. A histogram is an optimal choice for graphical representation as it deals with continuous data and shows the distribution of this data across set intervals. To perform a complete analysis, Callie might also calculate other statistical measures such as the mean, median, and standard deviation, which give her more insight into her data set's central tendency and variability.