Statistical+Vocabulary


 * __Statistical & Measurement Terms __**


 * **Analytic scoring: **The use of a scoring key containing an ideal response to judge the competence or proficiency of student responses on an assessment. Example:


 * **Balanced Assessment **: An approach to assessment where formative classroom assessments are used in concert with large-scale summative assessments. Both are of equal importance as they each serve a unique purpose.


 * **Correlation: **Measures the strength and direction of a relationship between two variables. Uses the correlation coefficient to describe the relationship.


 * **Correlation Coefficient: **Ranges from -1.00 to 1.00. A positive correlation means that as one variable increases, the other variable increases. A negative correlation means that as one variable increases, the other variable decreases. The closer the correlation coefficient is to 1.00, either positive or negative, the stronger the relationship is. If a correlation coefficient is 0, no linear relationship exists.


 * **Criterion Referenced: **Performance interpreted in relation to a specified standard.


 * **Criterion-related Validity: **The extent to which a test-score is related to an outcome measure/criterion.


 * **Dependent Variable: **The variable that is expected to change as a result of the independent variable. Test scores are expected to change as a result of hours of study. It should be the first column in a data table and the horizontal axis in a graph.


 * **Descriptive Statistics: **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">Statistics that summarize or describe a set of scores in a sample. Measures of central tendency and measures of dispersion are descriptive statistics.


 * **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">Distractor: **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">An incorrect choice within a multiple choice item.


 * **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">Evaluation: **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">Process used to judge information from one source such as assessment scores or from multiple sources.


 * **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">Formative assessment: **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">Evaluation conducted while a creative process is under way, designed and used to promote growth and improvement in a student’s performance or in a program’s development. Examples include (but not limited to): pre/post tests, portfolios, benchmark tests, quizzes, teacher observations.


 * **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">Hard Copy: **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">Paper reports distributed from a testing company. Provides performance information for an individual student, classroom, school, system or state.


 * **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">Independent Variable: **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">The variable that affects the dependent variable. For instance the strand you choose (independent variable) would affect the scores you get (dependent variable).


 * **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">Inferential Statistics: **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">Using the results found in a sample to make inferences regarding the entire population. **We will NOT be using inferential statistics today**!


 * **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">Interval Scale: **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">A measurement scale that has equal units.


 * **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">Linear Relationship: **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">A relationship that mimics the form of a straight line. As one variable increases, the other increases. Or alternately, as one variable increases, the other decreases.


 * **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">Mean: **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">A measure of central tendency; the arithmetic average of all of the scores.


 * **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">Multiple Regression Equation: **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">Using multiple input variables to predict an outcome variable.


 * **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">Negatively Skewed Distribution: **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">The mean is lower than the median. Therefore, low extreme scores are pulling the distribution down the number line (to the left).


 * **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">Nominal Scale: **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">A measurement scale that provides names or categories. It cannot be ordered or arranged.

<span style="font-family: 'Courier New'; mso-fareast-font-family: 'Courier New'; msofareastfontfamily: 'Courier New'; msolist: Ignore;">o <span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">Observing how students or subjects interact with their environment.
 * **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">Observational Research: **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">Research that takes place in a natural setting.


 * **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">Ordinal Scale: **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">A measurement scale that has the property of order but does not have equal distances between the scores. Example (class rank, dress sizes)


 * **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">Pearson //r:// **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">The statistical operation used to yield the correlation coefficient on interval or ratio data.


 * **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">Percentile Rank: **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;"> Scores are ranked and range from 1-99. A percentile reveals the percentage of students who score at or below a particular score. If a student achieves at the 60th percentile, he/she has performed better than 60% of the data set or norm group.


 * **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">Performance assessment: **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">A formal assessment method in which a student’s skill in carrying out an activity and producing a product is observed and judged. Examples include (but not limited to): construction of a project; completion of an essay, research paper, or a science lab).


 * **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">Pilot Test: **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">A test administered to gain information on the appropriateness of the items, administration guidelines, or other aspect of the test before it becomes operational.


 * **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">Positively Skewed Distribution: **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">The mean is above the median. There are extreme high scores pulling the distribution up the number line (to the right).


 * **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">Predictive Validity: A type of criterion-related validity. **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">The degree to which test scores correlate to future criterion measures.


 * **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">Qualitative Research: **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">Gathering historical or current subjective information. An in-depth study of relatively few cases where the information gained cannot easily be generalized.


 * **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">Quantitative Research: **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">Gathering and analyzing information that is quantifiable or can easily be converted to numbers.


 * **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">Range: **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">A measure of dispersion. The distance between the highest and lowest scores of a distribution.


 * **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">Ratio Scale: **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">A measurement scale that has a true zero point and equal units between scores.


 * **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">Reliability: **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">The degree to which test scores are consistent, reliable, and replicable.


 * **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">Research: **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">Using scientific inquiry to gain factual information.


 * **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">Sample: **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">A sub-set of data taken from a parent population.


 * **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">Skewed Distribution: **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">A distribution that is not a normal bell-shaped curve. It is not symmetrical.


 * **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">Standard Deviation: **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">A numerical value that describes the ‘average’ deviation of all scores in a distribution. It provides a value that describes the spread of scores from the mean and is expressed in the same unit of measurement as the original scores.


 * **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">Standard Error of Measurement (SEM): **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">The application of a test’s reliability to an individual student score. It is used to provide a range where a student’s true test score may fall within a certain level of confidence.


 * **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">Standard Score: **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">Describes the location of a score within a set of scores. The distance of the score from the mean is described in standard deviation units.


 * **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">Stanines: **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">A 9 point standard score scale with a mean of 5 and a standard deviation of 2.


 * **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">Statistical Significance: **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">What is observed in the sample has met a specific probability level of occurring by chance in the population. The typical probability level is < .05. Therefore, if a test has met this significance level, we can expect the observed difference to occur in the population less than 5% of the time.

<span style="color: black; font-family: Symbol; mso-bidi-font-family: Symbol; mso-bidi-font-size: 9.5pt; mso-fareast-font-family: Symbol; msobidifontfamily: Symbol; msobidifontsize: 9.5pt; msofareastfontfamily: Symbol; msolist: Ignore;"> · **<span style="color: #292526; font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-font-size: 9.0pt; mso-hansi-theme-font: minor-latin;">Statistics **<span style="color: #292526; font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-font-size: 9.0pt; mso-hansi-theme-font: minor-latin;"> are methods to collect, process and interpret data. There are two types of statistics <span style="color: black; font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-font-size: 9.0pt; mso-hansi-theme-font: minor-latin;">descriptive <span style="color: #292526; font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-font-size: 9.0pt; mso-hansi-theme-font: minor-latin;">and <span style="color: black; font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-font-size: 9.0pt; mso-hansi-theme-font: minor-latin;">inferential <span style="color: #292526; font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-font-size: 9.0pt; mso-hansi-theme-font: minor-latin;">. Descriptive used to describe or summarize our observations and inferential to make predictions or estimates.


 * **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">Summative assessment: **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">An evaluation designed to present conclusions about a student’s performance. Examples include (but not limited to): End-of-unit tests, state assessments, final exams.


 * **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">Validity: **<span style="font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-hansi-theme-font: minor-latin;">The extent to which a test measures what it intends to measure and the inferences that can be made from the assessment are meaningful.

<span style="color: black; font-family: Symbol; mso-bidi-font-family: Symbol; mso-bidi-font-size: 9.5pt; mso-fareast-font-family: Symbol; msobidifontfamily: Symbol; msobidifontsize: 9.5pt; msofareastfontfamily: Symbol; msolist: Ignore;">· **<span style="color: black; font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-bidi-font-size: 9.5pt; mso-hansi-theme-font: minor-latin;">Confidence intervals **<span style="color: black; font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-bidi-font-size: 9.5pt; mso-hansi-theme-font: minor-latin;"> take into account the fact that the students tested in any particular year might not be representative of students in that school across the years. Confidence intervals control for this sampling error or variation across years by promoting schools or subgroups that come very close to achieving their annual thresholds, thus meeting their specific AYP Targets.