Final Exam Flashcards
A psychologist is studying the effect of eating ice cream on memory performance. She assigns participants into groups that eat 1, 2, or 3 scoops one hour before they all take a memory test. What term best describes the role of “scoops of ice cream” in this study?
independent variable
Sum of Squares (SS)
Σ(X –M)^2
Variance (SD^2)
SD^2 = SS/N
Standard Deviation (SD)
square root of variance
To be scientific, a theory must be testable. This means the theory must be
falsifiable
A researcher expects that baboon mothers are generally more protective of their female offspring than their male offspring. When the researcher observes baboons in the wild, he focuses more of his attention on the mother-with-female offspring interactions, and takes more detailed notes, than when witnessing mother-with-male offspring interactions. Follow-up analysis demonstrated that the experimenter’s increased attention to mother-with-female offspring interactions actually caused the mothers to behave in a more protective way. Which of the following problems is evident?
Experimenter reactivity, experimenter bias
Where does a Cohen’s d effect size of -1.39 fall in terms of Jacob Cohen’s suggested conventions?
Large
What’s the point of Geoff Cumming’s slogan about a confidence interval, “It might be red!”?
It might not capture the true population mean from which the sample was drawn
In psychological research, a fact is something that can be precisely and objectively measured, like the diameter of the circles drawn in a sociogram. A ____ is the term for an inferred state/characteristic, something that can’t be directly measured, such as intelligence, anxiety, implicit self-inflation
construct
Which of the following is necessary to establish causation?
Alternative explanations have been ruled out, Covariation of the events, A time-order relationship
A particular standardized test has a population mean score of 75 and standard deviation of 7.5, and the scores are normally distributed. If a person’s score places them at the 5th percentile on this test (from the bottom), what is this person’s score?
z*σ + x
Score = (-1.64*7.5) + 75 = -12.3 + 75 = 62.7
The median is typically a better measure of central tendency than the mean in which of the following cases?
the distribution is highly skewed
Which of these describes the shape of a frequency distribution that has clearly been affected by a ceiling effect?
negatively skewed, skewed left
The results of a study measuring reaction time in response to a stimulus show a mean of 3.50 seconds and a standard deviation of 1.30 seconds. This allows us to calculate that a participant with a Z-score of +1.5 took ___ seconds to respond to the stimulus
score = z*σ + x
1.5(1.3) + 3.5 = 5.45
Which of these is a Z-score you would use if conducting a two-tailed Z test with an alpha level of 0.01?
2.58
A Z-score of 2.53 means that the score is ________
2.53 standard deviations above the mean
When there is no actual difference between the populations being studied, but the researcher rejects the null hypothesis, what kind of statistical decision error has occurred?
Type 1, false positive
If a measurement instrument gives consistent scores, the technical term we use to describe this is
reliability
The accuracy or goodness of an instrument’s functioning is referred to by the technical term
validity
When interpreting a boxplot, what does the top of the box tell you?
the 75th percentile score
By holding constant the content of an email, but randomly assigning professors to see one of 10 different types of names for the sender (suggesting different gender/race identities), what type of validity did Katherine Milkman strengthen?
internal & construct
A researcher is interested in children’s performance on a novel task after the 30 children from one classroom are randomly assigned to one of two groups: Group 1 children pretend to do the task (n = 15), while Group 2 children actually do the task (n = 15). Which of the following tests should the researcher use?
t-test for independent means
What does a very small p value, say p < .0001, tell you about the effect size of a study?
It tells you nothing about the effect size
power is the probability that…
if the research hypothesis is true, the experiment will support it.
When figuring the pooled population variance estimate in a t test for independent means,
the variance estimates based on each of the samples are averaged in such as way as to give more influence to the estimate based on more participants
A sample of children who scored highly on a measure of depression were given an energy drink once a day for one week. Three months later, their scores on the depression measure averaged significantly lower. The researcher concluded that the energy drink intervention was promising for reducing depression.
Which major type of confound (from among the nine we’ve studied) is most threatening to this researcher’s budding belief that the energy drink intervention is reducing depression?
regression to the mean
How do we best ensure high interrater reliability?
Randomly check 20% of their ratings
Which random assignment approach is best to use when sample sizes available for experimental conditions are small? The
matched
Professor Smyth once taught Intro to Social Psychology at 6pm on Tuesdays and Thursdays. He noticed that his students were far more likely to miss on Thursdays and he wondered whether his Thursday attendance rate was significantly different from the University’s overall attendance rate for Thursday classes. Fortunately, he was able to obtain the mean UVA Thursday attendance rate from University administrators. Which of the following tests would be most appropriate for his question?
Single sample t test
A t distribution for df = 20 will have ____ tails compared to the Z distribution, so the cut off scores for that t distribution will be ____ .
fatter; more extreme
