Which of the following is true about the mean?

The mean, or average, is a measure of central tendency calculated by summing all the values in a dataset and then dividing by the number of values. One significant characteristic of the mean is its sensitivity to outliers, which are data points that differ markedly from other observations. If an outlier is present, it can skew the mean, making it either higher or lower than the central tendency of the majority of the data. This is particularly problematic in datasets where outliers can disproportionately influence the average, leading to a potentially misleading representation of the data.

To clarify the context of the other choices, the mean is not always equal to the median; they can diverge in skewed distributions. While the mean does provide a measure of central tendency, calling it the "most precise" could be misleading; precision can depend on the data structure and presence of outliers. Lastly, means cannot be calculated for categorical data because the mean requires numerical values, whereas categorical data comprises distinct categories without inherent numeric implications.