EPPP: RESEARCH METHODS AND
STATISTICS QUESTIONS AND ANSWERS
WITH SOLUTIONS 2024
Independent Variable - ANSWER variable the researcher believes has an effect on the other variable;
always has at least two levels
Dependent Variable - ANSWER variable that's expected to be affected by the other variable
Moderator Variable - ANSWER affects the direction and/or strength of the relationship between
independent and dependent variables
A study finds CBT is more affective in treating social anxiety in adolescents whose parents are
authoritative. In this situation, parenting style is the what? - ANSWER Moderator
Mediator Variable - ANSWER explains the relationship between independent and dependent variable
Therapy leads to more realistic thinking which, in turn, leads to reduced anxiety. What is the mediator
variable? - ANSWER realistic thinking
Extraneous Variable - ANSWER an unintentional part of research study, affects the relationship between
the IV and DV, makes it difficult to determine if an apparent effect of the IV on the DV is actually due to
the IV
Nominal Scale - ANSWER divides people into unordered categories (e.g. gender, eye color, DSM
diagnosis); numbers can be assigned to categories but are simply a label
Ordinal Scale - ANSWER divides people into categories ordered in terms of magnitude, can conclude one
person has more or less of characteristic being measured but can't determine how much more or less;
e.g. likert scale
Interval Scale - ANSWER assigns people to ordered categories with the difference between adjacent
categories being equal; does not have absolute zero point; e.g. IQ scores
,Ratio Scale - ANSWER assigns people to ordered categories, with the difference between adjacent
categories being equal and the scale having an absolute zero point; e.g. weight, income
able to draw conclusions about data because of absolute zero
Bar Graphs - ANSWER used with nominal and ordinal data, categories listed on X axis,
numbers/percentages/observations listed on low to high on y axis
Histograms - ANSWER used with interval and ratio data, scores listed in order on x axis,
numbers/percentages on y axis, no space between bars
Frequency Polygons (Line Graphs) - ANSWER used with interval and ratio data, dots placed above each
score/interval, location of dot represents number of percentage of observations, dots connected with a
line
Normal Distribution - ANSWER A symmetrical, bell-shaped curve, with a majority of the scores falling in
the middle of the possible range and few scores appearing toward the extremes of the range.
- 68% = 1 standard deviation
- 95% = 2 standard deviations
- 99% = 3 standard deviations
Positively Skewed Distribution - ANSWER few scores in positive tale (high side)
Negatively Skewed Distribution - ANSWER few scores in the negative tail (low side of distribution)
Mean, median and mode of negatively skewed distribution - ANSWER mean = lowest
median = middle
mode = highest
mean, median, and mode of positively skewed distribution - ANSWER mean = highest
median = middle
, mode = lowest
Leptokurtic Distribution - ANSWER sharper peak and flatter tails than normal distribution
Platykurtic Distribution - ANSWER Flatter and more spread out than a normal curve.
(Memory: 'Plat' sounds like 'flat')
Classic Test Theory - ANSWER observed score = true score + error
i.e. X = T + E
Reliability Coefficient (r) - ANSWER range from 0-1.0; interpreted as the amount of variability in obtained
test scores that's due to T
e.g. r = .80 means 80% variability is T, 20% = E
70% or higher often considered minimum acceptable
test-retest reliability - ANSWER consistency of scores overtime, involves administering test to sample of
examinees and readministering at a later time, correlating the two sets of scores
useful for trait but not state measurements
alternate forms reliability - ANSWER consistency of scores over time with different forms of the test,
correlating scores from the same examinees on two different forms
Internal Consistency Reliability - ANSWER consistency of scores over different test items, useful for tests
designed to measure a single content domain or aspect of behavior
Coefficient Alpha (cronbach's alpha) - ANSWER a method of measuring internal consistency reliability,
used for administering test to the sample and calculating inter-item consistency
Kuder-Richardson 20 (KR-20) - ANSWER a method of measuring internal consistency reliability, used
when tests are dichotomously measured
e.g. correct/incorrect
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