When Sample Points Are Hugging the Center Line of a Control

question 15

True/False

When sample points are hugging the center line of a control chart,it usually indicates that the sample data is drawn from two populations.

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Definitions:

Standard Error of Measurement

The range of scores where we would expect a person’s score to fall if he or she took the instrument over and over again—in other words, where a “true” score might lie. It is calculated by taking the square root of 1 minus the reliability and multiplying that number by the standard deviation of the desired score.

Median

A measure of central tendency that is the middle score, or the score for which 50% of scores fall above and 50% fall below. In a skewed curve or skewed distribution of test scores, the median is generally the most accurate measure of central tendency since it is not affected by unusually high or low scores.

Standard Error of Measurement (SEM)

The margin of error in an individual's score, representing the variability in scores if the test were administered multiple times.

Test-Retest Reliability

A measure of consistency where the same test administered to the same group of individuals at two different points in time produces similar results.