Qualifying Exams Robinson- Terms for Research (blue)
the type (positive or negative) and degree of relationship
between 2 variables. Does not prove causation.
average distance that cases within a
distribution of scores vary from the mean
these describe individual statistics/test
scores in relation to the bell curve
normal curve/ bell curve
is a graphical representation of a normal distribution. For anything you measure, results across a large population distribute themselves symmetrically. In a normal distribution, the mean median and mode are all equal and the distribution is symmetrical across
the mean (one half mirrors hte other). The tails are asymptotic in that they come closer and closer to the horizontal axis, but never touch. 68% fall within
one SD. 95%fall within 2 SD's and 99% fall within 3 SD's. (Internal percentages= 34%, 13.5%, 2%). skewed right=positively skewed and is caused by extreme scores
at the high end that pull the mean higher than the median (midpoint). skewed left is opposite.
an expression of an individual score in a way that
conforms to standard deviation units. For example, 1.5 is one and a half standard deviation units above the mean and -.25 is one-quarter of a standard deviation units below the mean. These are useful in comparing scores across different settings , testing situations and tests.
o sometimes called a McCall T is a standard score resulting
from a z score transformation T= z(10)+50. The advantage= eliminates negative
numbers or fractions.
arithmatic average. measure of central tendency
midpoint. the number in the middle of a distribution (15
numbers, this would be the 8th in order)
a measure of central tendency
the most frequently occurring number in a
measure of central tendency
distance between highest and lowest
a measure of variability
how far apart numbers are (how spread out they are
from the mean)
Standard Error of measurement (SEM)-
These are found in standardized tests and are a measure of how much observed scores vary from a true score. The smaller the SEM= the more reliable the test.
3 ways to describe a distribution of a set of scores:
3 measures of central tendency-
established by comparison with another
test or measure of the same criteria.
is subjective. for example, does the test
fairly cover what was taught or what experts agree content is appropriate for measurement
identifies numerically the relationship between 2 variables (from -1 to 1 with midpoint of 0 that means no
evaluation aimed at guiding the nextinstructional step
results interpreted relative to thesuccess rate of other test takers
results interpreted relative to #of test items answered correctly,without reference to the success of other test takers.
used to identify strengths and weaknesses of a tool or process so that they might be revised for future use.
aimed at summarizing a segment of achievement (at the end of instruction) (ie, generating a grade or other symbol of achievement)
how dependable the test is. The consistency
with which something is accomplished.
accuracy. Does the test measure what it says it
one of three ways to describe a set of scores. Answers the question "How wide are the differences between the scores?" These can include range, standard deviation and variance.