The statement 'we can be 95% confident that the true score falls within the range 89–100' illustrates which concept?

The statement 'we can be 95% confident that the true score falls within the range 89–100' illustrates which concept?

• A. Confidence interval around the observed score
• B. Inter-rater reliability
• C. Test-retest reliability
• D. Standard deviation

Answer: (A)

Confidence intervals for a true score express the precision of measurement. In true score theory, an observed score includes random error, so the real value you’d get without error is the true score. Saying we’re 95% confident that the true score lies between 89 and 100 communicates that, given the observed data and the estimated measurement precision (the standard error), the true score is expected to fall within that range. The 95% level means that, if we repeated the measurement many times, about 95% of the such intervals would contain the true score. This is about estimation accuracy, not about how consistently raters score (inter-rater reliability), how stable scores are over time (test-retest reliability), or the spread of observed scores (standard deviation).

Confidence intervals for a true score express the precision of measurement. In true score theory, an observed score includes random error, so the real value you’d get without error is the true score. Saying we’re 95% confident that the true score lies between 89 and 100 communicates that, given the observed data and the estimated measurement precision (the standard error), the true score is expected to fall within that range. The 95% level means that, if we repeated the measurement many times, about 95% of the such intervals would contain the true score. This is about estimation accuracy, not about how consistently raters score (inter-rater reliability), how stable scores are over time (test-retest reliability), or the spread of observed scores (standard deviation).