Which of the following statements about scales of measurement is true?

The statement that only ratio scales provide a true zero point is accurate when considering the different types of scales of measurement used in statistics. Ratio scales not only have an absolute zero that indicates the complete absence of the variable being measured, but they also allow for meaningful comparisons between values, making them the most comprehensive type of measurement scale.

In comparison, other scales such as interval scales do not have a true zero point; the zero does not imply a lack of the quantity being measured. For instance, on a Celsius temperature scale, zero degrees does not mean the absence of temperature; it is simply a point on the scale. Ordinal scales allow for rankings but do not convey the magnitude of differences between ranks, and nominal scales provide categorization without a numerical value or order.

Thus, the statement about ratio scales providing a true zero point is critical to understanding the levels of data measurement and informs how various statistical analyses can be appropriately conducted.