Understand By The Term Reliability

1. Explain in a short paragraph what you understand by the term “reliability”. (2)

a. Reliability means that a rater or instrument is consistent and reliable in their measurements from trial to trial. When a measurement is reliable it can be reproduced over and over again and still consistently be free from error. However, it is impossible for a measurement to be completely free of error. Therefore, it is important that the measurement error is calculated. This is the difference between the observed and true values. A reliable measure will have a small measurement error.

2. Explain why the intraclass correlation coefficient is preferred to Pearson’s correlation coefficient as a measure of reliability? (2)

a. The Intraclass Correlation (ICC)

Known groups validity is when the validity of a measurement is determined by the degree to which the instrument can detect different scores between the groups. This test is used when the groups are already known to vary on the variables being tested and determines how sensitive the instruments detection of difference is.

Example: Known groups validity may be used to validate an instrument that is created to measure the amount of body image anxiety that exists between groups. It would be expected that a group of people diagnosed with anorexia would score higher on body image anxiety than a group of healthy individuals. Therefore, if the measurements gathered by the instrument followed this pattern we would conclude that the measure was valid. A finding of no difference between the group diagnosed with anorexia and the healthy group would lead to the conclusion that the measurement was not valid because the instrument was not able to detect this difference.

6. In order to compute the 95% confidence interval for Functional reach test (mean) or [Pre_FRT], you need to know 2 pieces of information about the Pre_FRT score in this sample. (3)

a. What are these 2 pieces of information?

i. Sample mean and SEM(standard error of the