Certified Rehabilitation Counselor Practice

A standard score based on the normal distribution curve with a mean equal to 0 and a standard deviation equal to 1 is known as what?

1. T-score

2. Z-score

3. Percentile rank

4. C-score

The correct answer is: Z-score

The correct answer is Z-score because a Z-score is a statistical measurement that describes a value's relationship to the mean of a group of values. Specifically, it tells you how many standard deviations a data point is from the mean, which is defined as 0 in this context. In a standard normal distribution, which is a bell-shaped curve, the Z-score allows for comparison between different data sets by standardizing the scores, enabling the understanding of how individual values relate to the overall distribution. In contrast, a T-score is based on a different standard deviation and is often used when sample sizes are small. Percentile rank indicates the percentage of scores in a distribution that a particular score is higher than, but it does not provide information about the standard deviation directly. A C-score is less commonly used and does not correspond to the standard normal distribution as Z-scores do. Thus, understanding the Z-score’s role in assessing data within the context of the normal distribution makes it the most appropriate choice.