Speaker 1: Welcome back, everybody. Well, we did assessments this week. It
took a look a lot of statistics, So this week's
ten question practice quiz will consist of some of the
material we covered earlier in the week. Question number one
A researchers investigating in rare neurological syndrome and tracks three
affected individuals over a five year period, collecting detailed qualitative
behavioral neuroimaging data. What is the prominent primary methodological limitation
of this research design A low external validity B higher
risk of carryover effects or see low internal consistency.
Speaker 2: A is the correct answer case.
Speaker 1: Studies involving a very rich, small, specific, simple size offer
rich detail, but heavily limit the ability to generalize the
findings and the broader populations.
Speaker 2: That's external validity.
Speaker 1: Aganizational psychologists evaluates a new workplace.
Speaker 2: This is question number two wellness and let me repeat that.
So question number two.
Speaker 1: An organizational psychologist evaluates a new workplace wellness initiative by
measuring employee job satisfaction scores monthly for six months before
the program starts and monthly for six months following the
completion of the program. This research structure is best classified
as what a regression does continuity design, B factorial design
or C time series design.
Speaker 2: The answer is C. Time series design involves.
Speaker 1: Tracking trends over time by taking multiple distinct observations both
before and after a specific intervention is introduced. So it's
a time zeries design, again, involving tracking trends over time
by taking multiple distinct observations before and after a specific
intervention is introduced. Question number three. A clinical trial evaluates
the impact of treatment types CBT versus medication and client
age group adolescent versus adult on depression severity scores. The
study utilizes a two times two factorial design. Which of
the following statements is true regarding this design, A it
evaluates two independent variables and each containing two levels. It
evaluates four independent variables containing one level. Or C it
evaluates a single independent variable across four distinct measurement periods.
If you said A, you're right, it's A evaluates two
independent variables containing two levels. See in factorial notation, the
number of digits represents the number the number of independent variables,
so we started with two slash times two factorial design.
Two represents the digital the number of independent variables and
the value of Each digit indicates how many levels that
specific variable has. Each has two, so two times two.
Factorial design is two iv and two levels. Question number four.
A developmental psychologist wants to completely minimize error variance caused
by individual participant differences like personality or intelligence while testing
the cognitive effects of three different educational mobile apps. So again,
demental psychologists wants to completely minimize error variants caused by
individual differences while testing the cognitive effects of three different
educational mobile apps.
Speaker 2: Which design choice is most appropriate.
Speaker 1: Between subjects design with random assignment, A cross sectional design
utilizing stratified sampling, A within subjects design utilizing counterbalancing.
Speaker 2: If you said C, that's correct.
Speaker 1: So within subjects design, the same participants experience all conditions,
meaning each person acts as their own baseline control and
individual differences are perfectly controlled. Counterbalancing must be used alongside
it to eliminate the risk of order effects. Let me
see if this might help clear it up. A little
bit of statistics is in your game. Look at you
mix the experimental setup for this. Imagine you're testing the
impact of three different desktop environments on a participant's ability
to spot errors in a complex data set. Condition as
a standard clutter desktop with constant pop up on your computer.
Condition P is a clean minimalist desktop with all notification silence,
and Condition C is a specific ambient desktop featuring a subtle,
loopable background.
Speaker 2: Video of a fireplace.
Speaker 1: So again you're looking to see how different digital environments
affect a person's focus.
Speaker 2: Instead of recruiting.
Speaker 1: Three separate groups, to recruit one group of thirty participants
and every single one of them completes the task under
all three conditions, so you have phase one acting as
their own baseline. Because participant five might naturally have the
attention span of a zen master, where Participant twelve gets
distracted by shiny objects. Between subjects design would require massive
sample sizes to average out these personal traits, but with
a within subject design, Participant five's performance in the clutter
environment is compared directly to their own performance in the
minimalist environment, So individual differences in baseline focus, intelligence, or
even how much coffee they drank are controlled because the
person remains identical across all three conditions. I hopefully that
helps that one number five. A study finds a statistically
significant correlation P value of less than point zero one
and R value of point four five.
Speaker 2: That's the correlation number.
Speaker 1: Between a clinician's total years of experience in patient program
retention rates.
Speaker 2: That's what they find.
Speaker 1: So a study found statistically significant correlation between a clinician's
total years of experience and patient program retention rates. A
critic points out that highly experienced clinicians also tend to
practice and well through areas with better public transit, which
could explain the retention. We would call this, by the way,
a confounding variable. This critique highlights which methodological issue A
A third variable problem, B low statistical conclusion validity or
d I mean sorry C order effect.
Speaker 2: The answer is A.
Speaker 1: The third variable problem occurs when an unmeasured variable, in
this case, the neighborhood, wealthy, and transit, correlates with both
the predictory and the outcomes, creating a misleading causal appearance
and providing why correlation does not equal causation.
Speaker 2: Number six.
Speaker 1: The researcher measures treatment outcomes using a classification system where
symptoms severity is marked as mild, moderate, or severe. What
scale of measurement does this classification system represent? A nominal,
b ordinal, or C interval. If you said ordinal, you're right.
Ordinal scales categorize data into a distinct rank order. However,
the exact mathematical distance between the ranks is only unequal
and unknown. Number seven, an investigator wants to determine if
a new therapeutic module causes a reduction in generalized anxiety.
Due to a minister limitations at the clinic, the researcher
cannot randomly assign patients to conditions.
Speaker 2: Instead, they utilize.
Speaker 1: A pre existing therapy group for the treatment and a
different pre existing group as the control. The study is
best described as what a true experimental design A or
B quasi experimental non equivalent control group design or see
a naturalistic observation study.
Speaker 2: If you said B, you're right.
Speaker 1: This design compares a treatment and control group, but lacks
the random assignment component, relying instead on pre existing intact groups,
hence quasi experimental non equivalent control group design.
Speaker 2: Number eight.
Speaker 1: A study conducted in an ultra controlled lab environment demonstrates
a massive reduction in depressive symptoms. However, when clinicians attempt
to implement the same protocol in busy, fast paced community
mental health centers, the treatment fails to show significant benefits.
This discrepancy indicates that the original lab study possessed what
high internal validity but low external validity, low internal validity
but high external validity, or see low statistical conclusion validity
and high attrition bias.
Speaker 2: If you said a you're right.
Speaker 1: Highly controlled lab settings isolate variables well to establish clear causation,
high internal validity, but often failed to generalize into more
complicated real world conditions low external validity. Question number nine.
When interpreting the results of a two way a nova
within a factorial design, a researcher notes, of the combination
of treatment type and client age produces a distinct, non
parallel pattern of treatment outcomes on the graph. Demonstrates what
the presence of a significant what a main effect for
treatment type be interaction effect or ce selection threat. So,
when interpreting the results of a two way in nova
within a factorial design, a researcher notes, of the combination
of treatment type and client age produces a distinct, non
parallel pattern of treatment outcomes on the graph. If you
said interaction effect, You're right. It occurs when the impact
of one independent variable depends directly on the level of
another in the pendent variable. Visually, a significant interaction is
always represented by non parallel or intersecting lines on a graph,
and lastly to number ten to ensure that carryover effects,
practice effects, or participant fatigue do not distort the data.
In a within subject study evaluating three separate memory strategies,
the investigator alters the sequence in which the strategies are
practiced across different subgroups. This control technique is known as what.
Speaker 2: So again, we're looking at? What is it called?
Speaker 1: When the research you're evaluating within subjects three separate memory strategies,
the investigator alters a sequence in which the strategies are practiced.
Is it random sampling, B stratification or C counterbalancing? If
you said, see counterbalancing your rights systematically varies. Counterbalancing systematically
varies or randomizes the presentation order of conditions across participants
to distribute and cancel out potential order effects like fatigue
or practice effects, because those are going to have an impact. Well,
that's it for your ten practice questions.
Speaker 2: I hope you did well.
Speaker 1: If not, you can always hear it again and continue
to practice.
Speaker 2: Thanks everyone for listening.