Correlation
Look at the correlation matrix showing the results (table 1). The correlation between Age and ____ is .27.
TV use (hours)
Is there a relationship between having a job [yes or no] and going to Disney [yes or no]? Which statistic supports your claim?
Yes because p < .001
Look at the independent samples t-test comparing the perceptions of women's faces. What are the two groups being compared?
Groups 1 and 2 [judging vs. giving lectures]
Which of the following is an appropriate research question for a paired samples t-test?
A) Do men and women differ in their levels of job satisfaction?
B) Do students perform better on an exam after receiving tutoring compared to before?
C) Is there a relationship between hours of sleep and GPA?
D) Are math scores different among freshmen, sophomores, and juniors?
B) Do students perform better on an exam after receiving tutoring compared to before?
A researcher wants to determine if social media platform usage (Instagram or Facebook) is associated with political affiliation (Democrat or Republican). They survey 300 college students about their preferred social media platform and political beliefs.
chi-square test of association
Is r a descriptive statistic or an inferential statistic?
descriptive
Look at the correlation matrix (table 1). Can you conclude that TV use (hours) leads to worse sleep (hrs) for the participants?
No. You cannot make a causal claim from a correlation.
Look at the first chi-square test (table 2). What belongs in the blanks?
Having a job (____) increased the likelihood that someone had been to Disney land, more than not having a job (____).
75%
25%
Look at the results of the t-test comparing Group 1 (judging) and Group 2 (giving) and then Fill in the blanks.
People who are judging lectures (____) have equal perceptions compared to giving lectures (____)
M = 5.09, SD = 1.06
M = 5.04, SD = 1.03
A researcher conducts a paired samples t-test and finds t(29) = 2.87, p = .007. What does this mean?
A) There is a significant difference between the two time points
B) There is no significant difference between the two time points
C) The effect size is large
D) The correlation between the two variables is strong
A) There is a significant difference between the two time points
A professor examines whether the number of hours of sleep before an exam is related to exam scores. They collect data from 150 students, recording their sleep hours and test scores (out of 100 points).
correlation
Which measure of central tendency is most affected by extreme values (outliers)?
Mean (A)
Look at the correlation matrix (table 1) for sleeping behaviors. Finish this sentence for the statistically significant finding: The more TV use (hours) that a participant reported the...
...worse their memory was.
Look at the following statistic describing the relationship between Major [Psychology or Engineering] and studying preference [alone or in a group]. What can you conclude from the following statistical sentence?
χ²(1, N = 200) = 5.87, p = .015, φ = 0.17
There is a significant difference.
What assumption does an independent samples t-test make about the two groups?
A) The groups are related
B) The groups have the same number of participants
C) The groups come from populations with equal variances
D) The dependent variable is categorical
C) The groups come from populations with equal variances
A researcher measures stress levels in students before and after finals week and finds t(49) = 1.23, p = .22. What should they conclude?
A) Students’ stress levels significantly changed after finals
B) Students’ stress levels did not significantly change after finals
C) The sample size is too small to draw any conclusions
D) The correlation between stress and finals week is strong
B) Students’ stress levels did not significantly change after finals
A psychologist tests whether a 4-week meditation program reduces stress levels. They measure stress scores (on a 10-point scale) before and after the program for 50 participants.
dependent samples t-test
A researcher reports that test scores have a mean of 80 and a standard deviation of 5. What does the standard deviation tell us?
A) The average test score
B) The most common test score
C) The spread of scores around the mean
D) The highest and lowest test scores
The spread of the scores around the mean (C)
Look at the correlation matrix (Table 1). Write the statistical sentence that you would use to describe the relationship between Memory Ability and TV use (hours).
r (48)= .42, 95% CI = [-0.61, -0.10], p = .003
Using Table 4., explain the relationship without using numbers.
Engineering students were more likely to prefer studying in groups, while Psychology students were more likely to study alone.
How strong is the effect in the independent samples t-test? Report both the number and the words that describe that strength.
d = .046
weak effect
A study tests memory recall before and after sleep deprivation. The mean recall score drops from 85 to 75, and the t-test is significant. What does this suggest?
A) Sleep deprivation significantly reduces memory recall
B) There is no effect of sleep deprivation on memory recall
C) The results are invalid unless the sample size is large
D) The test should be re-run using an independent t-test
A) Sleep deprivation significantly reduces memory recall
A cognitive psychologist investigates whether drinking coffee improves memory recall. They randomly assign 40 participants to either a coffee group (who drink a cup before testing) or a no-coffee group (who do not drink coffee). After 30 minutes, both groups complete a memory recall test (score out of 20).
independent samples t-test
Which of the following is a measure of variability (dispersion)?
A) Mean
B) Median
C) Standard Deviation
D) Mode
Standard Deviation (C)
If a correlation between 2 variables is the following: r (713) = -.16, p < .001, 95% CI [-.23, -.08] -- What can you conclude about the result?
There is a significant, negative relationship between the two variables, as 1 increases the other decreases.
The result is likely to apply to a population as well.
What is the complete inferential statistical sentence for the relationship between sexual orientation and religious affiliation?
χ2 (1, N=80) = 10.24, p < .001, φ = .36
What is the complete statistical sentence for the independent samples t-test?
Write the statistical sentence and the words to explain what is happening.
t (77) = 0.207, p = .836, d = 0.0499
No effect.
No differences between groups.
What is the complete statistical sentence for the dependent samples t-test?
Write the statistical sentence and the words to explain what is happening.
t (78) = 2.81, p = .006, d = 0.316, 95% CI [0.0889, 0.541]
significant effect.
Nervousness rated higher than mens faces
A researcher measures students' satisfaction with their study habits and with their time management skills.
One hypothesis is that the more satisfied they are with their study habits, the more satisfied they are with their time management skills.
The second hypothesis is that students will be more satisfied with their study habits than their time management skills.
correlation
paired samples t-test
Draw a positive skewed distribution for me.
drawn on board