Extreme Scores
Extreme Scores - Related Videos
01:06
Introduction to z Scores
0 Views •
2023
A z score (or standardized value) is measured in units of the standard deviation. It tells you how many standard deviations the value x is above (to the right of) or below (to the left of) the mean, μ. Values of x that are larger than the mean have positive z scores, and values of x that are smaller than the mean have negative z scores. If x equals the mean, then x has a zero z score. It is important to note that the mean of the z scores is zero, and the standard deviation is one. z scores help...
01:17
z Scores and Area Under the Curve
0 Views •
2023
z scores are the standardized values obtained after converting a normal distribution into a standard normal distribution. A z score is measured in units of the standard deviation. The z score tells you how many standard deviations the value x is above (to the right of) or below (to the left of) the mean, μ. Values of x that are larger than the mean have positive z scores, and values of x that are smaller than the mean have negative z scores. If x equals the mean, then x has a z score of zero.
01:22
Absolute and Local Extreme Values
0 Views •
2026
The highest and lowest values of a function, relative to a reference axis, are known as extreme values. These include absolute maximum and absolute minimum values, which represent the highest and lowest points the function reaches across its entire domain. Within a restricted portion of the function, the highest and lowest values are referred to as local maximum and local minimum values, respectively.Periodic functions, such as sine and cosine, show extreme values at infinitely many points due...
09:44
Manual Muscle Testing: A Method of Measuring Extremity Muscle Strength Applied to Critically Ill Patients
0 Views •
Cited by 135 •
2011
Survivors of acute respiratory distress syndrome (ARDS) and critical illness frequently develop long-lasting muscle weakness. Manual muscle testing (MMT) is a standardized clinical examination commonly used to measure strength of peripheral skeletal muscle groups. This video demonstrates MMT using the 6-point Medical Research Council scale.
26:48
Induction and Clinical Scoring of Chronic-Relapsing Experimental Autoimmune Encephalomyelitis
0 Views •
Cited by 27 •
2007
This video demonstrates the induction and clinical scoring of an animal model of multiple sclerosis: chronic-relapsing experimental autoimmune encephalomyelitis in DA rats. The disease, induced by immunizing rats with an emulsion containing whole rat spinal cord and complete Freund's adjuvant, presents clinical signs resembling the human disease.
FAQs
An extreme score can represent a genuine individual difference, sampling variation, or measurement error. These possibilities have different implications: a person may truly show atypical performance, a sample may contain an unusual observation by chance, or the recorded value may not accurately reflect the person’s performance. Consequently, researchers should interpret the score’s source before drawing psychological conclusions.
A z score translates a raw score into its distance from the sample mean in standard-deviation units. This gives researchers a consistent way to judge how far an observation lies from the center of its reference distribution, rather than relying only on the original score’s numerical size. In psychological data analysis, that relative position helps flag observations requiring closer review.
Removing an extreme score can alter the analysis in opposite ways. If the value is a problematic observation, exclusion may improve the suitability of statistical tests by reducing a concern about their assumptions. If the value reflects meaningful psychological variation, exclusion may conceal that variation. The decision therefore requires reviewing the score rather than treating extremeness alone as sufficient justification.
A basic review begins with the raw score and the sample mean and standard deviation. Researchers can then express the observation as a z score, inspect how far it lies from the reference distribution, and consider whether it reflects individual variation, sampling variation, or measurement error. This sequence supports a reasoned decision about interpretation and subsequent analysis.
Researchers should investigate an extreme score when it could affect interpretation, signal a measurement concern, or challenge assumptions of a statistical test. Review is especially important before deleting the observation, because the same value may be either a genuine atypical performance or an error-related result. Examining its possible source helps preserve meaningful psychological information while supporting sound analysis.
In psychology, reviewing extreme scores supports both measurement and data analysis. It can help identify outliers, evaluate whether statistical-test assumptions remain plausible, and clarify how an atypical performance should be interpreted. The resulting judgment is not limited to labeling a value unusual; it connects the observation to measurement quality and to the purpose of the analysis.