Which function is used to visualize the frequency of data values within a dataset?

The histogram function is specifically designed to visualize the frequency distribution of data values within a dataset. By creating a graphical representation that displays the number of occurrences (frequency) of different ranges (bins) of data values, a histogram allows users to quickly assess the shape of the data distribution, identify any patterns, and observe the concentration of values. This makes it an essential tool in exploratory data analysis, enabling analysts to intuitively understand the underlying characteristics of the dataset.

In contrast, the fit function is generally used to determine how well a particular model or distribution fits the data but does not create a frequency visualization. The kurtosis function provides a measure of the "tailedness" of the probability distribution of a real-valued random variable but does not visualize frequency. Meanwhile, mean absolute percentage deviation measures accuracy in forecasting and is not related to visualizing data frequencies. Thus, the histogram function is the clear choice for visualizing the frequency of data values.