## PSYC 355 Exam 1

## PSYC 355 Exam 1 Liberty University Answers

- The paired-samples t test has three assumptions, including all but:
- The correct formula for effect size using Cohen’s d for a single-sample t test is:
- A study by Bettmann (2007) published in the Journal of the American Psychoanalytic Association assessed whether the attachment relationships between adolescents and their parents change as a result of a residential wilderness treatment experience for the adolescents. Participants completed the Adolescent Attachment Questionnaire at the start and at the end of the wilderness program. Which statistical test would we use to determine whether the wilderness treatment affected attachment relationships?
- For an independent-samples t test, there were 8 participants in Group 1 and 11 participants in Group 2. The total degrees of freedom were:
- The single-sample t test compares a sample mean to a population mean when:
- A clinical researcher was interested in determining whether his interventions were effective in minimizing depression symptoms among his participants. To assess the effectiveness of his treatment program, he administered a depression inventory prior to his treatment and after his treatment. He hypothesized that depression scores would be lower at time two compared to time one. He then compared the mean differences between the two groups and found that his treatment was effective. The dependent variable in this study is:
- When scientists call a hypothesis test conservative, they mean that it is:
- The formula for the degrees of freedom for the single-sample t test is:
- A p level of 0.05 corresponds to a confidence interval of ________%.
- The formula for the research hypothesis for a paired-samples t test is:
- The appropriate symbolic representation of corrected variance for a sample is:
- The comparison distribution for an independent-samples t test is a distribution of:
- Which of the following statements is true about the assumptions of the independent- samples t test?
- The critical cutoffs for a two-tailed, paired-samples t test with seven participants at a p level of 0.01 are:
- Which of the following reports of statistical results are in appropriate APA format?
- The critical cutoff(s) for a two-tailed, paired-samples t test with 23 participants at a p level of 0.05 is (are):
- A clinical researcher was interested in determining whether his interventions were effective in minimizing depression symptoms among his participants. To assess the effectiveness of two of his treatment programs, he administered a depression inventory after his treatment for two different groups of clients, each receiving a different treatment. He hypothesized that depression scores would be different between the two groups. The researcher’s hypothesis is:
- The numerator (top portion) of the ratio for calculating all the t statistics contains:
- If the standard deviation for a population, as estimated from a sample, is s = 10.23, then the standard error for a sample size of N = 20 is:
- In an independent-samples t test, how is the research hypothesis symbolized?
- The appropriate hypothesis test to use for a between-groups design with two groups is a(n):
- In a(n) ________, one sample is compared to a population for which we only know the mean during hypothesis testing.
- Which of the following illustrates the APA format for reporting statistically significant results for an independent-samples t test?
- A researcher studies 45 volunteer citizens from a small community and asks them about the amount of caffeine (in milligrams) they ingest before and after lunch each day. The null hypothesis for this paired-samples study could be:
- A researcher investigates if the extent to which people care about keeping their house clean and neat changes if they are given new things in that home. He follows eight families that were selected to receive home makeovers, assessing their cleanliness before the makeover and after. Given the following confidence interval [–1.26, 0.95], make a decision about the hypotheses.
- Why do we divide by N – 1 rather than by N when estimating a population standard deviation from the sample standard deviation?
- According to the null hypothesis, the mean difference for the comparison distribution in a paired-samples t test is:
- In a(n) ________, each participant is assigned to only one group in order to compare mean differences.
- Unnithan, Houser, and Fernhall (2006) were interested in whether playing the game Dance Dance Revolution (DDR) affected the heart rate of overweight and nonoverweight adolescents differently. A group of 22 adolescents, 10 classified as overweight and 12 as not overweight, played DDR for 12 minutes, during which time the researchers measured each participant’s heart rate. Which statistical test should the researchers use to analyze their data?
- Twenty people participate in a weight-loss program for two months. Their weights after the two months are compared to their starting weights. What kind of mean difference might we expect if the null hypothesis is true for a paired-samples t test?
- A clinical researcher was interested in determining whether his interventions for depression were effective in minimizing depression symptoms among his participants. To assess the effectiveness of his treatment program, he administered a depression inventory prior to his treatment and after his treatment. He hypothesized that depression scores would be lower at time two compared to time one. He then compared the mean of the differences between the two groups to a known standard and found that his treatment was effective. Which statistical test was the researcher most likely to have used to test his hypothesis?
- Identify the formula for the single-sample t test.
- When performing a single-sample t test, an effect size of 0.80 would be interpreted as a:
- For the single-sample t test, the confidence interval is centered around the:
- To determine our critical values or cutoffs for an independent-samples t test, we use:
- A researcher collects 15 data points that yield a mean of 9.164 and a standard deviation (based on N – 1) of 2.377. What is the standard error for the distribution of means?
- A study found statistically significant results for a hypothesis tested with an independent-samples t test. The author of the study reported her effect size for the test as 1.24. What is true of the two sample means?
- In a paired-samples test, the comparison distribution is a distribution of:
- A researcher conducts a single-sample t test and finds statistical significance at the 0.01 level. The effect size is then calculated and found to be 0.04. What might you conclude about the findings?
- The second step in conducting the single-sample t test involves ________ and
- In a paired‐samples test, the comparison distribution is a distribution of:
- For an independent‐samples t test, there were 8 participants in Group 1 and 11 participants in Group 2. The total degrees of freedom were:
- Twenty college students experience the effects of alcohol on reaction time. They perform very basic timed responses in a driving simulator both before and after consuming several alcoholic beverages. The researcher collects a reaction time result for each of the 20 students before and after intoxication, for a total of 40 measures. What are the degrees of freedom for this study?
- A researcher studies 45 volunteer citizens from a small community and asks them about the amount of caffeine (in milligrams) they ingest before and after lunch each day. The null hypothesis for this paired‐samples study could be:
- In addition to reporting the results of statistical hypothesis testing, it is also recommended that researchers to report:
- When we know the population mean but not the population standard deviation, which statistic do we use to compare a sample to the population?
- When performing a single‐sample t test, an effect size of 0.80 would be interpreted as a:
- As the sample size becomes smaller, the t distributions become:
- We have learned three t tests, including all of the following except:
- The comparison distribution for an independent‐samples t test is a distribution of:
- A study found statistically significant results for a hypothesis tested with an independent‐samples t test. The author of the study reported her effect size for the test as 0.82. According to Cohen’s convention, this effect size is considered:
- The two populations compared in an independent‐samples t test include the:
- Which of these is NOT an assumption of the paired‐samples t test?
- The formula for the degrees of freedom for the dependent‐samples t test is:
- A psychologist is interested in whether working memory is influenced by sleep loss. The psychologist administers a measure of working memory to a group of subjects at 8 A.M. on Day One of the study and then again at 8 A.M. on Day Two of the study, after keeping the subjects awake the entire night. Does sleep loss affect working memory? What is the statistical analysis we would perform to answer this question?
- The formula for the research hypothesis for a paired‐samples t test is:
- According to the null hypothesis, the mean difference for the comparison distribution in a paired‐samples t test is:
- In a paired‐samples t test, the null hypothesis posits that the mean of the comparison distribution is:
- The formula for the degrees of freedom for the single‐sample t test is:
- A study by Bettmann (2007) published in the Journal of the American Psychoanalytic Association assessed whether the attachment relationships between adolescents and their parents change as a result of a residential wilderness treatment experience for the adolescents. Participants completed the Adolescent Attachment Questionnaire at the start and at the end of the wilderness program. Which statistical test would we use to determine whether the wilderness treatment affected attachment relationships?
- A clinical researcher was interested in determining whether his interventions were effective in minimizing depression symptoms among his participants. To assess the effectiveness of two of his treatment programs, he administered a depression inventory after his treatment for two different groups of clients, each receiving a different treatment. He hypothesized that depression scores would be different between the two groups. The researcher’s hypothesis is:
- s2pooled is the symbol for:
- Which of the following illustrates the correct APA format for reporting statistically significant results for an independent‐samples t test?
- Which example best illustrates APA’s standards for reporting descriptive statistics for an independent‐samples t test?
- For the single‐sample t test, the confidence interval is centered around the:
- The formula for the total degrees of freedom for the independent‐samples t test is:
- The mean of the comparison distribution for the null hypothesis of an independent‐ samples t test is:
- The appropriate symbolic representation of corrected variance for a sample is:
- The formula “H0: μ1 = μ2” is used to represent the:
- In a(n) ________, one sample is compared to a population for which we only know the mean during hypothesis testing.
- Mehl (2007) published in the journal Science the results of an extensive study of 396 men and women comparing the number of words uttered per day by each sex. Which statistical test should Mehl use to analyze the data?
- The critical cutoffs for a two‐tailed, paired‐samples t test with seven participants at a p level of 0.01 are:
- The numerator (top portion) of the ratio for calculating all the t statistics contains:
- The formula for the null hypothesis for a paired‐samples t test is:
- A psychologist is interested in whether working memory is influenced by sleep loss. The psychologist administers a measure of working memory to two groups of subjects. The subjects in one group were kept awake for the entire night and the subjects in the other group maintained their normal sleep schedules. Which statistical analysis would we perform to answer the question “Does sleep loss affect working memory?”
- A p level of 0.05 corresponds to a confidence interval of ________%.
- According to the null hypothesis, the mean difference for the comparison distribution in a paired‐samples t test is:
- To determine our critical values or cutoffs for an independent‐samples t test, we use:
- If the standard deviation for a population, as estimated from a sample, is s = 10.23, then the standard error for a sample size of N = 20 is: