Question

If a revised version of a test is found to be more reliable, then this will increase the Standard Error of Measurement (assuming that the standard deviation of the revised test is the same as the original).

a) True
b) False

Answer 1

The statement is false because an increase in the reliability of a test actually leads to a decrease in the Standard Error of Measurement (SEM), making the test scores more precise.

Step-by-step explanation:

If a revised version of a test is found to be more reliable, then this will decrease the Standard Error of Measurement (SEM), assuming that the standard deviation of the revised test is the same as the original. The statement is false. Let's explore why.

The SEM is a function of the test's standard deviation and its reliability. The formula for SEM is:

SEM = SD × √(1 - r)

Where SD is the standard deviation of test scores and r is the reliability coefficient of the test. An increase in the reliability (r) would lead to a decrease in the SEM, as the part subtracted from 1 becomes larger, making the product smaller. So, if the reliability of a test increases, all else being constant, the SEM decreases, not increases.

This means that a more reliable test will have a smaller SEM, which implies that the measurement from the test will be closer to the true score; that is, the test would be more precise in measuring what it’s intended to measure.