 Compares the various grading methods in a normal distribution. Includes: Standard deviations, cummulative precentages, percentile equivalents, Z-scores, T-scores, standard nine, percent in stanine - For Z-values in ecology, see Z-value.
In statistics, a standard score (also called z-score or normal score) is a dimensionless quantity derived by subtracting the population mean from an individual (raw) score and then dividing the difference by the population standard deviation. Image File history File links Download high resolution version (1200x687, 38 KB) File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ...
Image File history File links Download high resolution version (1200x687, 38 KB) File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ...
Z-value of an organism is the temperature, in degrees Fahrenheit, that is required for the thermal destruction curve to move one log cycle. ...
A graph of a bell curve in a normal distribution showing statistics used in educational assessment, comparing various grading methods. ...
In dimensional analysis, a dimensionless number (or more precisely, a number with the dimensions of 1) is a pure number without any physical units. ...
In statistics, mean has two related meanings: the average in ordinary English, which is more correctly called the arithmetic mean, to distinguish it from geometric mean or harmonic mean. ...
In probability and statistics, the standard deviation of a probability distribution, random variable, or population or multiset of values is defined as the square root of the variance. ...
The z score reveals how many units a case is above or below the mean. The z score allows us to compare the results of different normal distributions, something done with frequent research.
≈The standard score is not the same as the z-factor used in the analysis of high-throughput screening data, but is sometimes confused with it. This article is in need of attention from an expert on the subject. ...
It has been suggested that Virtual_high_throughput_screening be merged into this article or section. ...
The conversion process is called standardizing.
The standard score is:  .
where
- X is a raw score to be standardized
- σ is the standard deviation of the population
- μ is the mean of the population
The quantity z represents the distance between the raw score and the population mean in units of the standard deviation. z is negative when the raw score is below the mean, positive when above. In probability and statistics, the standard deviation of a probability distribution, random variable, or population or multiset of values is defined as the square root of the variance. ...
In statistics, mean has two related meanings: the average in ordinary English, which is more correctly called the arithmetic mean, to distinguish it from geometric mean or harmonic mean. ...
A key point is that calculating z requires the population mean and the population standard deviation, not the sample mean or sample deviation. It requires knowing the population statistics, not the statistics of a sample drawn from the population of interest.
But knowing the true standard deviation of a population is often unrealistic except in cases such as standardized testing, where the entire population is measured. In cases where it is impossible to measure every member of a population, the standard deviation may be estimated using a random sample. For example, a population of people who smoke cigarettes is not fully measured. Standardized testing is: in theory: a tool to ensure that student knowledge and aptitude in a given subject are examined with the same criteria across different schools. ...
A lit cigarette will burn to ash on one end. ...
When a population is normally distributed, the percentile rank may be determined from the standard score and ubiquitous tables. The normal distribution, also called Gaussian distribution (although Gauss was not the first to work with it), is an extremely important probability distribution in many fields. ...
The percentile rank of a score is the percentage of scores in its frequency distribution which are lower. ...
Standardizing in mathematical statistics In mathematical statistics, a random variable X is standardized using the theoretical (population) mean and standard deviation: Mathematical statistics uses probability theory and other branches of mathematics to study statistics from a purely mathematical standpoint. ...
A random variable is a mathematical function that maps outcomes of random experiments to numbers. ...
 where μ = E(X) is the mean and σ² = Var(X) the variance of the probability distribution of X. In statistics, mean has two related meanings: the average in ordinary English, which is more correctly called the arithmetic mean, to distinguish it from geometric mean or harmonic mean. ...
In mathematics and statistics, a probability distribution, more properly called a probability density, assigns to every interval of the real numbers a probability, so that the probability axioms are satisfied. ...
If the random variable under consideration is the sample mean: In mathematics and statistics, the arithmetic mean of a set of numbers is the sum of all the members of the set divided by the number of items in the set. ...
 then the standardized version is 
References - Abdi, H. "[1] ((2007). Z-scores. In N.J. Salkind (Ed.): Encyclopedia of Measurement and Statistics. Thousand Oaks (CA): Sage.".
External links Listen to this article ·
(info) This audio file was created from an article revision dated 2006- 07-09, and does not reflect subsequent edits to the article. (Audio help) More spoken articles - z-score calculator Convert between cumulative probability (Q) and z-score (standard score).
- Free z-Score (Standardized Score) Calculator Calculate z-score given sample mean, sample standard deviation and the unstandardized value.
Image File history File links Standard_score. ...
Image File history File links Sound-icon. ...
2006 (MMVI) is a common year starting on Sunday of the Gregorian calendar. ...
July 9 is the 190th day of the year (191st in leap years) in the Gregorian Calendar, with 175 days remaining. ...
Image File history File links Sound-icon. ...
See also |
Feeds |
Contact