Which term describes the measurement of an individual's deviation from the mean of a reference population?

Which term describes the measurement of an individual's deviation from the mean of a reference population?

• A. Z score
• B. P-value
• C. Chi-squared
• D. Comparative standard

Answer: (A)

A Z score describes how far an individual's value is from the mean of a reference population, expressed in units of the standard deviation. This standardization lets you compare a person’s position within the reference distribution regardless of the measurement scale, because it accounts for the spread of values. The idea is simple: subtract the reference mean from the individual's value and divide by the reference standard deviation. A positive result means the value is above the mean, a negative result means it is below. The other terms don’t measure deviation from the mean in standardized units: a P-value relates to the probability of observing the data under a null hypothesis, chi-squared is a test statistic for observed vs. expected frequencies, and comparative standard isn’t a standard measure for this purpose.

A Z score describes how far an individual's value is from the mean of a reference population, expressed in units of the standard deviation. This standardization lets you compare a person’s position within the reference distribution regardless of the measurement scale, because it accounts for the spread of values. The idea is simple: subtract the reference mean from the individual's value and divide by the reference standard deviation. A positive result means the value is above the mean, a negative result means it is below. The other terms don’t measure deviation from the mean in standardized units: a P-value relates to the probability of observing the data under a null hypothesis, chi-squared is a test statistic for observed vs. expected frequencies, and comparative standard isn’t a standard measure for this purpose.