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| It refers to the sample of test takers who are representative of the population for whom the test is intended. |
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| a bell-shaped curve showing a particular distribution of probability over the values of a random variable. |
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| the mode is a most common (frequent) value. |
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| "Middle value" of a list. The smallest number such that at least half the numbers in the list are no greater than it. |
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| The range of a set of numbers is the largest value in the set minus the smallest value in the set. |
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| The variance of a list is the square of the standard deviation of the list, that is, the average of the squares of the deviations of the numbers in the list from their mean. |
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| The standard deviation of a set of numbers is the rms of the set of deviations between each element of the set and the mean of the set. |
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Definition
- For individually administered tests, the point on test, associated with a given level of
functioning or skill, for which an examiner is confident, that all items prior to that item
would be answered correctly (considered too easy). The items below this point, although not
administered to the individual student, are afforded full credit. |
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Term
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Definition
The upper limit of ability that a test can effectively measure or for which reliable
discriminations can be made. Individual or groups scoring at or near the highest possible
score are said to have "reached the ceiling" of the test (i.e., a ceiling effect), and should, if
possible, be administered the next higher level of the test in order to obtain a more accurate
estimate of their ability. For individually administered tests, the ceiling refers to the point
during administration, after which, all other items will no longer be answered correctly
(considered too difficult), and results in the examiner stopping the administration of the test. |
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Term
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Definition
A type of derived score, which is a transformation of the raw score,
and whose score distribution in a specified population has convenient, known values for the
mean and standard deviation. Often this term is used to specifically denote z-scores (mean
=0.0 and standard deviation =1.0), and any linear transformation of z-scores. However,
Standard Scores can also be developed to provide a continuous score scale (developmental
scale) across different levels and forms of a test. Standard Scores permit the direct
comparison of examinees by placement of the scores on a common scale and, for this reason,
are useful for longitudinal comparisons |
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Term
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Definition
The percentage of scores in a specified distribution that fall at or
below the point of a given score. Percentile Ranks range in value from 1 to 99, and indicate
the status or relative standing of an individual within a specified group (e.g., norms group),
by indicating the percent of individuals in that group who obtained lower scores. |
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Term
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Definition
The name stanine is simply a derivation of the term "standard-nine" scale.
Stanines are normalized standard scores, ranging in value from 1-9, whose distribution has
a mean of 5 and a standard deviation of 2. Stanines 2 through 8, are equal to a ½ standard
deviation unit in width, with the middle stanine of 5 defined as the range of scores ¼ of a
standard deviation below to ¼ of a standard deviation above the mean. Stanines can, more
easily, be thought of as coarse groupings of percentile ranks (see below), and like percentile
ranks indicate the status or relative rank of a score within a particular group. |
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Term
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Definition
A type of standard score such that the distribution of the scores for a specified
population have a mean of 0.0 and a standard deviation of 1.0. The z-score indicates the
amount a student's score (X) deviates from the mean in relation to the standard
deviation (SD) of the group. |
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Definition
- A normalized standard score, having a mean of 50 and a standard deviation of 10.
T-Scores are a direct transformation of z-scores and range (roughly) from 20 to 80
(corresponding to approximately 3 standard deviations above and below the mean) |
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Term
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Definition
The chronological age in a defined population for which a given score is
the median (middle) score. An examinee assigned an age equivalent of 7-5 indicates that he
or she received the same score (raw score, scale score, standard score, etc.) as the average
child who is seven years, five months old. |
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Definition
In a test development context, a term that refers to the difficulty level of a
reading passage or other text related to a test or test item |
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Definition
- The degree to which accumulated evidence and theory support specific
interpretations of test scores entailed by the purposed uses of a test. Or more commonly
defined, the extent to which the test measures what it is intended to measure (i.e., the
accuracy of the test). |
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Term
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Definition
An interval between two values on a score scale within which, with
specified probability, a score or parameter of interest lies. An individual's test score
provides a good point estimate of the student's ability in a specific area. |
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Term
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Definition
A testing accommodation, as the term is used in connection with normreferenced achievement tests, refers to a change in the standard procedures for
administering the assessment. An accommodation is intended to neutralize, as much as
possible, the effect of a student's disability on the assessment process. Accommodations do
not change the kind of achievement being measured. However, as an important
consideration of test fairness, accommodations do change how that achievement is measured
for the express purpose of "leveling the playing field" for a student with a disability. If
chosen appropriately, an accommodation will neither provide too much or too little help to
the student who receives it. To the extent that accommodations used with a student are
chosen carefully and judged to be necessary, the anticipated effect is to reduce the impact of
the student's disability on the assessment process. That is, the student's responses are closer
to what would be expected from the student if that student had no disability. |
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