Stats Refresher Flashcards
Most commonly used measure of central tendency
Arithmetic mean
Tool that could be used to describe the amount of variability in a distribution
Average deviation
Numbers indicated of frequency also appear on the y-axis, and reference to some categorization appears on the x-axis
Bar graph
Two scores that occur with the highest frequency
Bimodal distribution
Joint probability distribution of two variables
Bivariate distribution
Indication of how much variances is shared by the X - and the Y -variables.
Coefficient of determination
Expression of the degree and direction of correspondence between two things
Correlation
Refers to an “eyeball gauge” of how curve the graph is
Curvilinearity
Set of test scores arranged for recording or study
Distribution
Instrument used to measure strength of hand grip
Dynamometer
In most meta-analytic studies, this is what typically expressed as correlation coefficient
Effect size
Collective influence of all of the factors on a test score or measurement beyond those specifically measured by the test or measurement
Error
Professional practice that is based on clinical and research findings
Evidence-based practice
Number of times each score occurred
Frequency distribution
Chart that contains a continuous line representing the frequencies of scores within a class interval
Frequency polygon
Diagram or chart composed of lines, points, bars, or other symbols that describe and illustrate data
Graph
Test-score intervals, also called class intervals, replace the actual test scores
Grouped frequency distribution
Graph with vertical lines drawn at the true limits of each test score (or class interval), forming a series of contiguous rectangles.
Histogram
Distance between the first quartile and the third quartile
Interquartile range
Contain equal intervals between numbers; each unit on the scale is exactly equal to any other unit on the scale; contain no absolute zero point.
Interval scales
The term testing professionals use to refer to the steepness of a distribution in its center
Kurtosis
Distributions that are generally described as relatively peaked
Leptokurtic
Standard score that retains a direct numerical relationship to the original raw score.
Linear transformation
Average value of set numbers
Mean
Act of assigning numbers or symbols to characteristics of things (people, events, whatever) according to rules; rules used in assigning numbers are guidelines for representing the magnitude (or some other characteristic) of the object being measured.
Measurement
Statistic that indicates the average or midmost score between the extreme scores in a distribution.
Measure of central tendency
Statistics that describe the amount of variation in a distribution.
Measures of variability
Middle score in a distribution, is another commonly used measure of central tendency.
Median
Distributions are generally described as somewhere in the middle
Mesokurtic
Family of techniques used to statistically combine information across studies to produce single estimates of the data under study.
Meta analysis
Most frequently occurring score in a distribution of scores
Mode
Simplest form of measurement; involve classification or categorization based on one or more distinguishing characteristics, where all things measured must be placed into mutually exclusive and exhaustive categories.
Nominal scale
Involves “stretching” the skewed curve into the shape of a normal curve and creating a corresponding scale of standard scores
Normalizing a distribution/Normalized standard score scale
Extremely atypical point located at a relatively long distance—an outlying distance—from the rest of the coordinate points in a scatterplot
Outlier
Can be the statistical tool of choice when the relationship between the variables is linear and when the two variables being correlated are continuous
Pearson correlation coefficient/ Pearson r
Permit classification, rank ordering on some characteristic is also permissible; imply nothing about how much greater one ranking is than another.
Ordinal scales
Relatively few of the scores fall at the high end of the distribution.
Positive skew
Distributions are generally described as relatively flat
Platykurtic
Equal to the difference between the highest and the lowest scores.
Range
Distribution of test scores (or any other data, for that matter) can be divided into four parts such that 25% of the test scores occur in each quarter.
Quartile scores
Number that provides us with an index of the strength of the relationship between two things.
Correlation coefficient
Has a true zero point; all mathematical operations can meaningfully be performed because there exist equal intervals between the numbers on the scale as well as a true or absolute zero point.
Ratio scale
Straightforward, unmodified accounting of performance that is usually numerical.
Raw score
Set of numbers (or other symbols) whose properties model empirical properties of the objects to which the numbers are assigned.
Scale
Graphic representation of correlation
Scatterplots
Nature and extent to which symmetry is absent.
Skewness
Equal to the interquartile range divided by
2.; measurement of how spread out a set of data is; also known as the quartile deviation.
Semi-interquartile range
Equal to the square root of the average squared deviations about the mean. More succinctly, it is equal to the square root of the variance.
Standard deviation
Thiis coefficient of correlation is frequently used when the sample size is small (fewer than 30 pairs of measurements) and especially when both sets of measurements are in ordinal (or rank-order) form.
Spearman Rho
Standard scores that take on whole values from 1 to 9, which represent a range of performance that is half of a standard deviation in width
Stanines
Composed of a scale that ranges from 5 standard deviations below the mean to 5 standard deviations above the mean.
T scores
Raw score that has been converted from one scale to another scale, where the latter scale has some arbitrarily set mean and standard deviation.
Standard score
The area on the normal curve between 2 and 3 standard deviations above the mean
Tail
Indication of how scores in a distribution are scattered or dispersed.
Variability
Equal to the arithmetic mean of the squares of the differences between the scores in a distribution and their mean.
Variance
Results from the conversion of a raw score into a number indicating how many standard deviation units the raw score is below or above the mean of the distribution.
z score
All scores are listed alongside the number of times each score occurred.
Frequency distribution
4 different levels or scales of
measurement
Nominal
Ordinal
Interval
Ratio
2 types of scale
Continuous scale
Discrete scale
2 types of FREQUENCY DISTRIBUTIONS
Simple frequency distribution
Grouped frequency distribution
3 types of graphs in FREQUENCY DISTRIBUTIONS
Bar graph
Frequency polygon
Histogram
Type of distribution where the mode, median and mean are all in the middle of the
distribution.
Symmetrical distributions
Type of distribution where the mode remains the most commonly occurring value, the median
remains the middle value in the distribution, but the mean is generally ‘pulled’ in the direction of the tails.
Skewed distributions
Bell-shaped, smooth, mathematically
defined curve that is highest at its center.
NORMAL CURVE
3 types of standard score
Z Scores
T Scores
Stanine
