Final answer:
Z-scores are not helpful for the public in general because they are based on a standard normal distribution, which may not apply to real-world data sets.
Step-by-step explanation:
Z-scores are not helpful for the public in general because they are based on a standard normal distribution, which assumes that the data follows a specific pattern. In reality, many real-world data sets do not follow this specific pattern and may have different means and standard deviations. Therefore, using z-scores to compare or analyze such data sets would not provide accurate or meaningful results.