Midterms 1 Flashcards
the act of assigning numbers or
symbols to characteristics of things according to
rules
Measurement
methods used to provide
concise description of a collection of quantitative
information
Descriptive Statistics
methods used to provide
concise description of a collection of quantitative
information
Descriptive Statistics
method used to make
inferences from observations of a small group of people
known as sample to a larger group of individuals
known as population
Inferential Statistics –
– the property of “moreness”
Magnitude
– the difference between two points
at any place on the scale has the same meaning as the
difference between two other points that differ by the
same number of scale units
Equal Intervals
– when nothing of the property being
measured exists
Absolute 0
a set of numbers who properties model
empirical properties of the objects to which the
numbers are assigned
Scale
takes on any value within the
range and the possible value within that range is infinite
- used to measure a variable which can theoretically be
divided
Continuous Scale –
– can be counted; has distinct, countable
values
- used to measure a variable which cannot be
theoretically be divided
Discrete Scale
– refers to the collective influence of all the
factors on a test score or measurement beyond those
specifically measured by the test or measurement
Error
Four Levels of Scales of Measurement
Nominal
Ordinal
Interval
Ratio
– involve classification or categorization
based on one or more distinguishing characteristics
- Label and categorize observations but do not make
any quantitative distinctions between observations
Nominal
rank ordering on some characteristics is also
permissible
- median
Ordinal
- contains equal intervals, has no absolute zero
point (even negative values have interpretation to it) - Zero value does not mean it represents none
Interval
has true zero point (if the score is zero, it means
none/null)
- Easiest to manipulate
Ratio
defined as a set of test scores arrayed
for recording or study
Distribution
– straightforward, unmodified
accounting of performance that is usually numerical
Raw Scores
– all scores are listed
alongside the number of times each score occurred
Frequency Distribution
being manipulated in the
study
Independent Variable
nonmanipulated
variable to designate groups
Quasi-Independent Variable –
statistics that
indicates the average or midmost score between the
extreme scores in a distribution
Measures of Central Tendency –
– the average of all the raw scores
- Equal to the sum of the observations divided by the
number of observations
Mean
the middle score of the distribution
- Ordinal, Interval, Ratio
- Useful in cases where relatively few scores fall at the
high end of the distribution or relatively few scores fall
at the low end of the distribution
Median
most frequently occurring score in the
distribution
Mode
an indication how scores in a
distribution are scattered or dispersed
Variability
statistics that describe the
amount of variation in a distribution
Measures of Variability
– equal to the difference between highest and
the lowest score
Range
– dividing points between the four quarters
in the distribution
▪ Specific point
Quartile
– equal to the square root of the
average squared deviations about the mean
Standard Deviation
also known as Gaussian Curve
o Bell-shaped, smooth, mathematically defined curve
that is highest at its center
Normal Curve –
– 2 – 3 standard deviations above and below the
mean
Tail
– right side of the graph
is mirror image of the left side
Symmetrical Distribution
nature and extent to which symmetry is
absent
Skewness
few scores fall the high end of the
distribution
▪ The exam is difficult
Positive Skewed
– when relatively few of the scores
fall at the low end of the distribution
▪ The exam is easy
Negative Skewed
– steepness if a distribution in its center
Kurtosis
relatively flat
Platykurtic
– relatively peaked
Leptokurtic
– somewhere in the middle
Mesokurtic
raw score that has been converted
from one scale to another scale
Standard Score
– results from the conversion of a raw score
into a number indicating how many SD units the raw
score is below or above the mean of the distribution
Z-Scores
– a scale with a mean set at 50 and a
standard deviation set at 10
T-Scores
– a method of scaling test scores on a nine-
point standard scale with a mean of five (5) and a
standard deviation of two (2)
Stanine
one that retains a direct
numerical relationship to the original raw score
Linear Transformation
required when the
data under consideration are not normally distributed
Nonlinear Transformation –
statistical method that uses a
sample data to evaluate a hypothesis about a
population
Hypothesis Testing
– states there is a change,
difference, or relationships
Alternative Hypothesis
– no change, no difference, or no
relationship
Null Hypothesis
used to
define concept of “very unlikely” in a hypothesis test
Alpha Level or Level of Significance
composed of extreme values that
are very unlikely to be obtained if the null hypothesis
is true
Critical Region
statistical hypotheses specify either an increase or a
decrease in the population mean
Directional Hypothesis Test or One-Tailed Test
– used to test hypotheses about an unknown
population mean and variance
T-Test
number that provides us
with an index of the strength of the relationship
between two things
Correlation Coefficient
an expression of the degree and
direction of correspondence between two things
Correlation
– used when two variables being
correlated are continuous and linear
Pearson r/Pearson Correlation
Coefficient/Pearson Product-Moment Coefficient
of Correlation
frequently used if the sample size is
small and when both sets of measurement are in
ordinal
Spearman Rho/Rank-Order Correlation
Coefficient/Rank-Difference Correlation
Coefficient
extremely atypical point located at a
relatively long distance from the rest of the
coordinate points in a scatterplo
Outlier
used for prediction
▪ Predict the values of a dependent or response
variable based on values of at least one
independent or explanatory variable
Regression Analysis
comparison or determining
differences
T-Test (Independent)
2 groups are equal
Equal Variance
groups are unequal
Unequal Variance
one groups
nominal (either matched or repeated measures) + 2
treatments
T-test (Dependent)/Paired Test
3 or more IV, 1 DV comparison
of differences
One-Way ANOVA
– 2 IV, 1 DV
Two-Way ANOVA
reject the null and accept the
alternative if [ obtained value > critical value ]
Critical Value
reject null and accept
alternative if
P-Value (Probability Value)
refer to the performances by defined groups
on a particular test
Norms –
an expression of the percentage of people
whose score on a tests or measure falls below a
particular raw score
Percentiles
average performance of different
samples of testtakers who were at various ages at the
time the test was administered
Age Norms
– developed by administering the test to
representative samples of children over a range of
consecutive grade levels
Grade Norms
derived from a normative sample
that was nationally representative of the population at
the time the norming study was conducted
National norms
– normative sample can be
segmented by any criteria initially used in selecting
subjects for the sample
Subgroup Norms
– provide normative information with
respect to the local population’s performance on some
tests
Local Norms
– certain tests have different
normative groups for age groups
Age-Related Norms
– tendency to stay at about the same level relative to one’s peers
Tracking
– compares each person with
the norm
Norm-Referenced Tests
– compares each person with
the norm
Norm-Referenced Tests
describes specific types
of skills, tasks, or knowledge that the test taker can
demonstrate
Criterion-Referenced Tests –
describes specific types
of skills, tasks, or knowledge that the test taker can
demonstrate
Criterion-Referenced Tests –
