Psych 100A quizzes (up to 7)

Grades on a psychology midterm have a mean of 80 and a standard deviation of 5. What is the z-score for an exam grade of 75 (report to one decimal)?

-1.0

A psychologist studying post-partum depression administered a questionnaire to 100 new mothers and obtained a mean depression score of 22 with a standard deviation of 4. What is the value of the standard error of the mean?

0.4

A sample of depression scores has a mean of 20 and a standard deviation of 5. Which of the following scores represents someone with unusually low depression (i.e., an outlier)? Select one: a. 10 b. 15 c. 18 d. 13

10

Consider the following set of depression scores: 11, 12, 12, 13, 15, 16, 17, 19, 22. What is the sample median?

15

Consider the following set of depression scores: 1, 2, 2, 3, 5, 6, 7, 9, 12, 13. What is the sample mode?

2

In a survey of hospital patients, the average age is 50 with a standard deviation of 10. Which of the following ages would definitely be considered an outlier (i.e., a score that is located in the tail of the distribution; an uncommon score)? Select one: a. 60 b. 20 c. 55 d. 40

20

Consider the following frequency distribution for a survey question asking about agreement on a political ballot initiative (the Frequency column is the same as the Count). Assuming that the total number of respondents is 250, what is the value for the frequency in the cell labeled X? https://ccle.ucla.edu/pluginfile.php/2597873/question/questiontext/2655211/3/15735305/picture10.jpg

25

Consider the following frequency distribution for a survey question asking about highest level of education (the Frequency column is the same as the Count). Assuming that the total number of respondents is 500, what is the value for the frequency in the cell labeled X? https://ccle.ucla.edu/pluginfile.php/2597873/question/questiontext/2655211/7/15735302/picture5.jpg

250

A depression questionnaire asks the following three items, each of which is measured on a 1 (Strongly disagree) to 5 (Strongly agree) scale. I felt that I had nothing to look forward to I felt down-hearted and blue. I felt that life was meaningless. Consider the following score profile: 2, 3, 4. What is the value of a scale score computed as the average level of agreement across the questions?

3

A psychologist is interested in determining whether a new online pain management program improves (reduces) pain scores for its participants. He assigns 20 subjects to the treatment condition and 20 to the control, and he measures pain intensity on a 1-10 scale. The treatment and control means are 7 and 5, respectively. Which of the following standard deviation values would produce the smallest standardized mean difference? Select one: a. The standard deviation does not influence the standardized mean difference b. 1 c. 3 d. 2

3

Consider the following set of scores: 1, 2, 2, 7, 8. What is the sample standard deviation (round to two decimals)?

3.24

Consider the following set of scores: 11, 12, 12, 17, 18. What is the sample standard deviation (round to two decimals)?

3.24

A sample of depression scores has a mean of 20 and a standard deviation of 5. Which of the following scores represents someone with unusually high depression (i.e., an outlier)? Select one: a. 22 b. 25 c. 30 d. 27

30

In a survey of hospital patients, the average age is 50 with a standard deviation of 10. What is the age of a respondent who is two standard deviations below the mean?

30

A depression questionnaire asks the following three items, each of which is measured on a 1 (Strongly disagree) to 5 (Strongly agree) scale. I felt that I had nothing to look forward to I felt down-hearted and blue. I felt that life was meaningless A researcher forms a scale score by averaging responses to the three items. What is the maximum value for the scale score?

5

Consider the following set of depression scores: 1, 2, 2, 3, 5, 6, 7, 9, 12, 13. What is the sample median?

5.5

In a survey of hospital patients, the average age is 50 with a standard deviation of 10. What is the age of a respondent who is zero standard deviations from the mean?

50

Consider the following set of depression scores: 1, 2, 2, 3, 5, 6, 7, 9, 12, 13. What is the sample mean?

6

In a survey of hospital patients, the average age is 50 with a standard deviation of 10. What is the age of a respondent who is one standard deviation above the mean?

60

A psychologist studying chronic pain administered a questionnaire to 100 chronic pain patients and obtained a mean pain rating of 6 with a standard deviation of 1. The standard error of the mean is .10. Which of the following interpretations is correct for the standard error? Select one: a. A sample mean based on N = 100 should differ from the population mean by 1 point, on average b. If the researcher took another sample, the mean would increase or decrease by .10 c. A sample mean based on N = 100 should differ from the population mean by .10, on average d. The average difference between a pain rating and the sample mean is .10

A sample mean based on N = 100 should differ from the population mean by .10, on average

A psychologist studying post-partum depression administered a questionnaire to a sample of 100 new mothers and obtained a mean depression score of 22 with a standard deviation of 4. The standard error of the mean is .40. Which of the following interpretations is correct for the standard error? Select one: a. The average difference between a depression score and the mean is .40 b. The sample mean based on N = 100 should differ from the population mean by 4, on average c. If the researcher took another sample of any size, the mean should change by .40, on average d. A sample mean based on N = 100 should differ from the population mean by .40, on average

A sample mean based on N = 100 should differ from the population mean by .40, on average

A researcher estimates the mean depression score at 15. Which of the following will produce the largest confidence interval (i.e., the widest range)? Select one: a. A sample size of 200 b. Sample size has no impact on the confidence interval c. A sample size of 100

A sample size of 100

A researcher finds the sample mean on the Beck depression inventory is 17. Which of the following will produce the smallest confidence interval (i.e., the smallest range)? Select one: a. A sample size of 100 b. Sample size has no impact on the confidence interval c. A sample size of 200

A sample size of 200

A psychologist studying post-partum depression administered a questionnaire to 200 new mothers and obtained a mean depression score of 22. What would the researcher need to do to obtain the parameter? Select one: a. Administer the depression survey to all new mothers in the US b. Administer the depression survey to a larger group of 10000 new mothers c. Administer the depression survey to a new sample of 200 mothers, then average the results d. Administer the depression survey to several samples of 200 mothers, then average the results

Administer the depression survey to all new mothers in the US

A researcher calculates the standard deviation of age and obtains a value of zero. Which of the following is true? Select one: a. All ages were below the mean b. Ages were equally distributed above and below the mean c. All ages were identical d. A mistake was made, the standard deviation cannot equal zero e. All ages were above the mean

All ages were identical

In which of the following situations will the standard deviation be the smallest? Select one: a. Half of the scores are above the mean and half are below the mean b. All scores are very different from the mean c. All scores are very similar to the mean d. All scores are identical

All scores are identical

In which of the following situations will the standard deviation be the largest? Select one: a. All scores are very similar to the mean b. Half of the scores are above the mean and half are below the mean c. All scores are identical d. All scores are very different from the mean

All scores are very different from the mean

A university runs a new class designed to improve the Freshman experience. The hypothesis is that participation in the new class will improve attitudes toward school. To evaluate the hypothesis, the research team assigns a sample of 100 incoming Freshman to the intervention class and 100 to a standard Freshman class load (control). Attitudes toward school were measured on a 10-point scale, and the students participating in the class showed better attitudes, with a standardized mean difference of .20. Which of the following interpretations is correct? Select one: a. Attitude scores improved by about 20% of a standard deviation unit b. Attitude scores for the student in the new class improved by 20% relative to the control group c. On a 1-10 scale, attitude scores improved by about 20% of one point d. Attitude scores improved by about 2 points (20% of the 10-point scale)

Attitude scores improved by about 20% of a standard deviation unit

Using a popular depression scale, a clinical researcher determines that a sample of new mothers has a depression mean of 19. Further, the study reports that there is a 95% probability that the range from 17 to 21 contains the true mean in the population of new mothers. The range being reported is known as the ______. Select one: a. Standard error b. Margin of error c. Confidence interval d. Standard deviation of estimates

Confidence interval

A researcher studying post-partum depression wants to summarize the scores with a measure of variability. Which of the following best describes her goal? Select one: a. Describe the typical score b. Describe the range in which most scores fall c. Compare scores to an established norm group d. Describe the degree to which scores differ

Describe the degree to which scores differ

A researcher studying post-partum depression wants to summarize the scores with a measure of central tendency. Which of the following best describes her goal? Select one: a. Compare scores to an established norm group b. Describe the range in which most scores fall c. Describe the typical score d. Describe the degree to which scores differ

Describe the typical score

The population standard deviation formula has N in the denominator, whereas the sample standard deviation formula has N-1 in the denominator. What is the rationale for using N-1 rather than N when computing the average distance from the center of the data? Select one: a. Dividing by N would make the sample standard deviation a more accurate estimate of the population standard deviation b. Dividing by N-1 would make the sample standard deviation a more accurate estimate of the population standard deviation c. We don't know the number of observations in the full population, so we use N-1 as an estimate of the number of observations

Dividing by N-1 would make the sample standard deviation a more accurate estimate of the population standard deviation

Which of the following variables is measured on an ordinal scale? Select one: a. Education level (less than HS, HS grad, some college, college grad) b. Treatment assignment (treatment vs. control) c. Ethnicity d. Number of Facebook friends

Education level (less than HS, HS grad, some college, college grad)

A poll of 772 registered voters found that 42% of respondents approve of Donald Trump's performance as President. The 42% value represents what quantity? Select one: a. Parameter b. Sample c. Estimate d. Population

Estimate

A researcher studying depression examines scores for males and females. Males had a mean depression score of 18 with a standard deviation of 6, while females had a mean depression score of 20 with a standard deviation of 8. In which group were depression scores most different? Select one: a. Females b. Males

Females

A sample of males has a depression mean of 20 and a standard deviation of 5, whereas a sample of females has a depression mean of 19 and a standard deviation of 4. In which group are depression scores most similar to one another? Select one: a. Females are more similar in their levels of depression b. Males are more similar in their levels of depression

Females are more similar in their levels of depression

A distribution of midterm exam scores has a strong positive skew. Which of the following is true? Select one: a. Most scores are moderate, somewhere in the middle b. Few people have very high scores c. Most scores are very high d. Few people have very low scores

Few people have very high scores

A test preparation company reports that, after taking their GRE preparation class, student scores increased. Which of the following sets of descriptive statistics would produce the smallest standardized mean difference? Select one: a. GRE class mean = 625 (SD = 150), control mean = 500 (SD = 150) b. GRE class mean = 625 (SD = 200), control mean = 500 (SD = 200) c. GRE class mean = 625 (SD = 50), control mean = 500 (SD = 50) d. GRE class mean = 625 (SD = 100), control mean = 500 (SD = 100)

GRE class mean = 625 (SD = 200), control mean = 500 (SD = 200)

Which of the following variables is measured on an interval (approximately continuous) scale? Select one: a. Treatment assignment (treatment vs. control) b. Education level (less than HS, HS grad, some college, college grad) c. Income (< 30K, 30K-50K, 50K-80K, 80K or higher) d. IQ

IQ

A computer-administered measure of prejudice presents participants with a statement about a particular ethic group and then records the amount of time it takes participants to respond to the prompt. What is the level of measurement for the reaction time variable? Select one: a. Ordinal b. Interval (Approximately Continuous) c. Quasi-Interval d. Nominal

Interval

A study examining the use of and engagement with Facebook asked participants about weekly minutes spent logged on. Which level of measurement describes this variable? Select one: a. Nominal b. Quasi-Interval c. Interval (Approximately Continuous) d. Ordinal

Interval

A study of post-partum depression includes a questionnaire item asking mothers to report the number of children in the family. Which level of measurement describes this variable? Select one: a. Quasi-Interval b. Ordinal c. Nominal d. Interval (Approximately Continuous)

Interval

A researcher wants to report the central tendency for gender. Which measures of central tendency can be computed for this variable? Note that the question is NOT asking which one you should use, but which one you could use. Check all that apply. Select one or more: a. Median b. Mean c. Mode

Mode

A researcher wants to use a measure of central tendency to summarize the ethnicity breakdown of his sample. Which measures of central tendency can be computed for this variable? Note that the question is NOT asking which one you should use, but which one you could use. Check all that apply. Select one or more: a. Mode b. Mean c. Median

Mode

Which measure of central tendency can take on more than one value? Select one: a. Median b. Mean c. Mode

Mode

A researcher asks respondents to report their income in a series of bins or categories: "Less than 20K", 20K-39K", "40K-59K", "60K-79K", "80K-99K", and "100K or higher". Which measures of central tendency can be computed for this variable? Note that the question is NOT asking which one you should use, but which one you could use. Check all that apply. Select one or more: a. Mode b. Median c. Mean

Mode and median

Consider the following set of depression scores: 11, 12, 12, 13, 15, 16, 17, 19, 22, 23. Suppose that the value of 23 changed to a 30. Which measure of central tendency would not be affected by this change? Check all that apply. Select one or more: a. Mode b. Median c. Mean

Mode and median

A researcher studying post-partum depression wants to report the central tendency for her depression scale score. Which measures of central tendency can be computed for this variable? Note that the question is NOT asking which one you should use, but which one you could use. Check all that apply. Select one or more: a. Mode b. Median c. Mean

Mode, median and mean

The population standard deviation formula has N in the denominator, whereas the sample standard deviation formula has N-1 (degrees of freedom) in the denominator. What is the rationale for using N-1 rather than N when computing the average distance from the center of the data? Select one: a. N-1 makes the sample standard deviation smaller than the standard deviation of the full population of scores b. N-1 makes the sample standard deviation closer to the standard deviation of the full population of scores c. N-1 makes the sample standard deviation larger than the standard deviation of the full population of scores

N-1 makes the sample standard deviation closer to the standard deviation of the full population of scores

A psychologist studying post-partum depression wants to estimate the mean depression level in the population of new mothers. Which sample size will yield a sample mean that is closer to the true population mean, on average? Select one: a. Both N = 100 and N = 500 will yield estimates that are equally close to the population mean b. N=100 c. N=500

N=500

A researcher studying post-partum depression computes the sample mean of 13 and a median of 22. Which of the following is most likely true about the distribution of depression scores? Select one: a. Positively skewed b. Negatively skewed c. Normally distributed d. Uniformly distributed

Negatively skewed

A national survey of smoking behavior classifies respondents into four ethnic groups: white non-Hispanic, black non-Hispanic, Hispanic, and other non-Hispanic. What is the level of measurement for this variable? Select one: a. Ordinal b. Nominal c. Interval (Approximately Continuous) d. Quasi-Interval

Nominal

Beta-carotene supplements have been thought to protect against cancer. A study published in the Journal of the National Cancer Institute randomly assigned women to receive a beta-carotene supplement or a placebo, and their health was studied over their lifetime. The outcome variable classified women according to whether cancer occurred or not. Which level of measurement describes the outcome variable (cancer vs. no cancer)? Select one: a. Nominal b. Quasi-Interval c. Ordinal d. Interval (Approximately Continuous)

Nominal

Beta-carotene supplements have been thought to protect against cancer. A study published in the Journal of the National Cancer Institute randomly assigned women to receive a beta-carotene supplement or a placebo, and their health was studied over their lifetime. Which level of measurement describes the treatment variable (beta-carotene supplement vs. placebo)? Select one: a. Ordinal b. Quasi-Interval c. Interval (Approximately Continuous) d. Nominal

Nominal

Across the entire Presidential election season, polling companies conduct hundreds of political opinion polls. Suppose that we obtained the percentage of Hillary Clinton voters from 100 different polls and created a histogram (sampling distribution) of the 100 estimates. Which of the following best describes the likely shape of this distribution? Select one: a. The shape of the distribution depends on the sample size b. Positively skewed c. Negatively skewed d. Uniform distribution e. Normal distribution

Normal distribution

A researcher is examining the age distribution for her sample and finds the following values: mean = 29.8, median = 29.6, mode = 30. Which of the following is most likely true about the shape of the age distribution? Select one: a. Positively skewed b. Uniformly distributed c. Negatively skewed d. Normally distributed

Normally distributed

A national survey of smoking behavior classifies respondents as non-smokers, non-daily smokers, and daily smokers. What is the level of measurement for this variable? Select one: a. Quasi-Interval b. Interval (Approximately Continuous) c. Nominal d. Ordinal

Ordinal

A popular depression scale classifies people into the following groups: no depression, mild depression, and clinical depression. Which level of measurement describes the depression variable? Select one: a. Ordinal b. Quasi-Interval c. Interval (Approximately Continuous) d. Nominal

Ordinal

A study examining the use of and engagement with Facebook asked participants to report the number of friends. Respondents chose between nine options of custom ranges, e.g., "10 or less", "11-50", "51-100", etc. Which level of measurement describes this variable? Select one: a. Quasi-Interval b. Interval (Approximately Continuous) c. Nominal d. Ordinal

Ordinal

A psychologist is interested in determining whether a new online pain management program improves (reduces) pain scores for its participants. He assigns 20 subjects to the treatment condition and 20 to the control, and he measures pain intensity on a 1-10 scale. At the end of the study the researcher finds an improvement, the standardized mean difference effect size of which is .30. Which of the following describes the meaning of this effect size value? Select one: a. Pain scores decreased by about 3 points (30% of the 10-point scale) b. Pain scores for the treatment group decreased by 30% relative to the control group c. Pain scores improved by about a third of a standard deviation d. On a 1-10 scale, pain scores decreased by about a third of a point

Pain scores improved by about a third of a standard deviation

A psychologist studying post-partum depression administered a questionnaire to 200 new mothers and obtained a mean depression score of 22. Suppose that the researcher could somehow administer the questionnaire to all new mothers in the US, finding a mean of 24. The 24 value represents what quantity? Select one: a. Sample b. Population c. Parameter d. Estimate

Parameter

Across the entire Presidential election season, three different polling companies conducted dozens of public opinion polls that estimate the percentage of Hillary Clinton voters in the population. To keep track of their results, the polling firms graph the estimates obtained across many random samples, and the resulting sampling distributions are shown below. Which of the polling firms obtained estimates with the most sampling error? https://ccle.ucla.edu/pluginfile.php/2597873/question/questiontext/2709795/10/15736064/Quiz%207%20fig%201.jpg Select one: a. Polling firm C's estimates exhibited the most sampling error b. Polling firm B's estimates exhibited the most sampling error c. The graphs provide no information about sampling error d. Polling firm A's estimates exhibited the most sampling error

Polling firm A's estimates exhibited the most sampling error

Across the entire Presidential election season, three different polling companies conducted dozens of public opinion polls that estimate the percentage of Hillary Clinton voters in the population. To keep track of their results, the polling firms graph the estimates obtained across many random samples, the results of which are shown below. Based on the sampling distribution graphs, which polling firm used the largest sample size? https://ccle.ucla.edu/pluginfile.php/2597873/question/questiontext/2709795/13/15736061/Quiz%207%20fig%201.jpg Select one: a. Polling firm A used the largest sample size b. Polling firm C used the largest sample size c. The graphs provide no information about sample size d. Polling firm B used the largest sample size

Polling firm C used the largest sample size

Across the entire Presidential election season, three different polling companies conducted dozens of public opinion polls that estimate the percentage of Hillary Clinton voters in the population. To keep track of their results, the polling firms graphed the estimates obtained across many random samples, and the sampling distributions are shown below. Which of the polling firms obtained estimates with the least amount of sampling error? https://ccle.ucla.edu/pluginfile.php/2597873/question/questiontext/2709839/4/15736065/Quiz%207%20fig%201.jpg Select one: a. The graphs provide no information about sampling error b. Polling firm A's estimates exhibited the least sampling error c. Polling firm B's estimates exhibited the least sampling error d. Polling firm C's estimates exhibited the least sampling error

Polling firm C's estimates exhibited the least sampling error

Suppose that a polling company surveyed all registered voters in the US and found that 45% approve of Donald Trump's performance as President. The group of all registered voters in the US represents what quantity? Select one: a. Sample b. Parameter c. Estimate d. Population

Population

A study of post-partum depression found that most mothers reported relatively low levels of depression, and higher levels of depression were relatively uncommon. What distribution shape best describes this variable? Select one: a. Uniform b. Negatively skewed c. Normal d. Positively skewed

Positively skewed

A study of post-partum depression includes a questionnaire item asking mothers to report the number of children in the family. Most mothers reported having only one child, and the number of mothers reporting 2, 3, and 4 children steadily decreased. What distribution shape best describes this variable? Select one: a. Uniform b. Normal c. Negatively skewed d. Positively skewed

Positively skewed

In 2011, the mean salary of an NFL player was $1.9 million, and the median salary was $770,000. Which of the following is most likely true about distribution of salaries? Select one: a. Negatively skewed b. Positively skewed c. Normally distributed d. Uniformly distributed

Positively skewed

A depression questionnaire asks the question, "I felt that I had nothing to look forward to." Respondents answered on a scale ranging from 1 (Strongly disagree) to 5 (Strongly agree). Which level of measurement describes this variable? Select one: a. Nominal b. Quasi-Interval c. Interval (Approximately Continuous) d. Ordinal

Quasi-interval

A research studying mathematics anxiety asks a sample of students the following question: "I feel that my anxiety toward math is a barrier for scoring well on the exam." Participants indicated their level of agreement or disagreement using a 5-point Likert-type rating scale ranging from 1 ("Strongly Disagree") to 5 ("Strongly Agree"). Which level of measurement describes this variable? Select one: a. Ordinal b. Quasi-Interval c. Interval (Approximately Continuous) d. Nominal

Quasi-interval

A study examining the use of and engagement with Facebook asked participants the following question: "I feel out of touch when I haven't logged onto Facebook for a while." Participants indicated their level of agreement or disagreement using a 5-point Likert-type rating scale ranging from 1 ("Strongly Disagree") to 5 ("Strongly Agree"). Which level of measurement describes this variable? Select one: a. Interval (Approximately Continuous) b. Nominal c. Ordinal d. Quasi-Interval

Quasi-interval

A study examining college student texting behavior asks the following questions: 1. How many times per hour do you send a text message? "0", "1-5", 6-10", "11-50", "50 or more". 2. Texting a friend while having a phone conversation with another friend is acceptable behavior: "Strongly Disagree", "Disagree", "Neutral", "Agree", "Strongly Agree" Which question would psychologists say most closely approximates an interval (approximately continuous) measurement scale?

Question 2

A study examining the use of and engagement with Facebook asked the following two questions: 1. How many friends do you actively follow on Facebook? "10 or less", "11-50", "51-100", "100 or more". 2. I feel out of touch when I haven't logged onto Facebook for a while: "Strongly Disagree", "Disagree", "Neutral", "Agree", "Strongly Agree" Which question would psychologists say most closely approximates an interval (approximately continuous) measurement scale? Select one: a. Neither approximate interval (continuous) data b. Question 1 c. Question 2 d. Both are approximate interval (continuous) data

Question 2

A psychologist studying post-partum depression administered a questionnaire to 200 new mothers and obtained a mean depression score of 22. The 200 respondents represent what quantity? Select one: a. Sample b. Parameter c. Estimate d. Population

Sample

Consider two samples of SAT scores. Sample 1 has 490, 492, 492, 497, and 500. Sample 2 has 490, 495, 500, 506, and 510. Which sample has a larger standard deviation (do not do the calculations)? Select one: a. Sample 1 b. Sample 2

Sample 2

Consider two samples of SAT scores. Sample 1 has 490, 495, 500, 506, and 510. Sample 2 has 490, 492, 492, 497, and 500. Which sample has a smaller standard deviation (do not do the calculations)? Select one: a. Sample 2 b. Sample 1

Sample 2

A Huffington Post poll of 772 registered voters found that 42% of respondents approve of Donald Trump's performance as President, whereas a similar CNN poll found that 44% approve. Which of the following is responsible for the difference between the two polls? Select one: a. Margin of error b. Sampling error c. Standard error d. Sampling distribution

Sampling error

Which of the following variables is measured on an ordinal scale? Select one: a. Treatment assignment (treatment vs. control) b. Self-reported health (poor, fair, good, excellent) c. Political affiliation d. Number of children in a family

Self-reported health (poor, fair, good, excellent)

A researcher is summarizing a sample of ages and reports that the average difference between a respondent's age and the sample mean is 8 years. Which measure of variability is she reporting? Select one: a. Standard deviation b. Range c. Variance

Standard deviation

A researcher reports that the average squared distance from the scores to the mean is 9 points. Which of the following is true about the standard deviation? Select one: a. Standard deviation could be < or > 9 b. Standard deviation > 9 c. Standard deviation < 9

Standard deviation < 9

A sample of depression scores has a mean of 20 and a variance of 25. Which of the following interpretations is true about the standard deviation? Select one: a. Standard deviation = 625 b. Standard deviation = 5 c. It depends on whether the sample or population formula was used d. Cannot determine without the raw data

Standard deviation = 5

The following sample of SAT scores has a standard deviation of 8.07: 490, 495, 500, 506, and 510. What would happen to the standard deviation value if the score of 510 changed to 550? Select one: a. Standard deviation > 8.07 b. Standard deviation < 8.07 c. Standard deviation could be < or > than 8.07

Standard deviation > 8.07

Suppose that researchers from 10 different universities each computed the mean depression score from a sample of 100 participants. The standard deviation of the estimates across the 10 samples is what quantity? Select one: a. Deviation value b. Standardized mean difference c. Standard deviation of scores d. Standard error

Standard error

Considering the frequency distribution below, what response category corresponds to the mode? https://ccle.ucla.edu/pluginfile.php/2597873/question/questiontext/2655218/1/15735357/13.png Select one: a. Agree b. Disagree c. Strongly disagree d. Strongly agree

Strongly agree

Considering the frequency distribution below, what response category corresponds to the mode? https://ccle.ucla.edu/pluginfile.php/2597873/question/questiontext/2655218/7/15735358/table%2016.jpg Select one: a. Strongly agree b. Strongly disagree c. Disagree d. Agree

Strongly disagree

A polling firm wants to know the percentage of registered Democratic voters that approve of Donald Trump's performance as President. What would the polling firm need to do to obtain an estimate? Select one: a. Survey all registered Democrats in the US b. Survey several different groups of 1000 registered Democrats, then average the results c. Survey a randomly selected group of 1000 registered Democrats

Survey a randomly selected group of 1000 registered Democrats

A polling firm wants to know the percentage of registered Democratic voters that approve of Donald Trump's performance as President. What would the polling firm need to do to obtain the parameter? Select one: a. Survey a randomly selected group of 1000 registered Democrats b. Survey all registered Democrats in the US c. Survey several different samples of 1000 registered Democrats, then average the results d. Survey a randomly selected group of 10,000 registered Democrats

Survey all registered Democrats in the US

College students are asked to rate the appropriateness of texting during class and texting while on a date. The standard deviation for texting in class is 1.25, and the standard deviation for texting on a date is 1.00. Which question elicited responses that were most similar? Select one: a. Texting during class b. Texting while on a date

Texting while on a date

A sample of depression scores has a mean of 20 and a standard deviation of 5. Which of the following interpretations is definitely true? Select one: a. The difference between the lowest and highest score is 5 points b. All scores are within ± 5 points from the mean c. The average difference between a score and the mean is 5 points d. 68% of scores are within ± 5 points from the mean e. The average squared difference between a score and the mean is 5 points

The average difference between a score and the mean is 5 points

IQ scores are normally distributed with a mean of 100 and a standard deviation of 15. Which of the following is true? Select one: a. The average difference between an individual IQ and the mean is 15 points b. The distance separating the middle 68% of the scores is 15 points c. The average squared difference between an individual IQ and the mean is 15 points d. All scores are within ± 15 points from the mean e. 95% of IQ scores are within ± 15 points from the mean

The average difference between an individual IQ and the mean is 15 points

A sample of depression scores has a mean of 20 and a variance of 25. Which of the following interpretations is definitely true? Select one: a. All scores are within ± 25 points from the mean b. 95% of scores are within ± 25 points from the mean c. At least some of the scores take on negative values d. The average difference between a score and the mean is 25 points e. The average squared difference between a score and the mean is 25 points f. The difference between the lowest and highest score is 25 points

The average squared difference between a score and the mean is 25 points

IQ scores are normally distributed with a mean of 100 and a variance of 225. Which of the following is true? Select one: a. 95% of IQ scores are within ± 225 points from the mean b. The distance separating the middle 68% of the scores is 25 points c. The average difference between an individual IQ and the mean is 225 points d. The average squared difference between an individual IQ and the mean is 225 points e. All scores are within ± 225 points from the mean

The average squared difference between an individual IQ and the mean is 225 points

A researcher studying aggressive behavior in children decides to report the median number of aggressive behaviors that children engage in during the observation period. Which of the following most likely describes the reason for this choice? Select one: a. The variable is a nominal scale b. The distribution of scores is skewed c. Scores are normally distributed d. There is more than one value for the mode

The distribution of scores is skewed

Suppose that we obtained the percentage of Trump supporters from 100 different polls of size N = 200 and constructed a histogram of the 100 estimates. Next, suppose that we obtained the percentage of Trump supporters from 100 different polls of size N = 1000 and graphed the 100 estimates (i.e., created a sampling distribution) Which of the two sampling distributions will have the larger standard deviation (e.g., will have estimates with greater variability around the center)? Select one: a. The estimates from samples of size 200 b. Both graphs will have nearly identical variability c. The estimates from samples of size 1000

The estimates from samples of size 200

After converting depression scores to the z-score metric, a study participant's score takes on a positive value. Which of the following is definitely true about this person's depression score? Select one: a. The individual is far above the mean b. The individual is above the mean c. The individual is far below the mean d. The individual is at the mean e. The individual is below the mean

The individual is above the mean

Researchers are interested in determining whether a smoking cessation intervention reduces smoking frequency. They assign 50 subjects to the treatment condition and 50 to the control, and measure smoking frequency on a 1-5 scale. At the end of the study the researcher finds that the treatment subjects improved, with a standardized mean difference effect size of .51. How would you characterize the impact of the new class on smoking behavior? Select one: a. The intervention had a large positive impact on smoking behavior b. The intervention had a moderate positive impact on smoking behavior c. The intervention had a small positive impact on smoking behavior d. The intervention had little to no impact on smoking behavior

The intervention had a moderate positive impact on smoking behavior

A Presidential opinion poll reports that 40% of registered voters approve of the job that Trump is doing as President, with a standard error of 2%. The quantity 1.96 x 2% = 2.92% is known as ______. Select one: a. The standard error b. The margin of error c. The confidence interval d. Sampling error

The margin of error

A psychologist studying post-partum depression administers a questionnaire to a sample of new mothers and obtains a mean depression score of 22. Considering the difference between this estimate and the parameter, which of the following is true? Select one: a. The sample size determines whether this estimate is higher or lower than the population mean b. The mean depression score in the population must be lower than 22 c. The mean depression score in the population must be higher than 22 d. The mean depression score in the population could be higher or lower than 22

The mean depression score in the population could be higher or lower than 22

Researchers are interested in determining whether a smoking cessation intervention reduces smoking frequency. They assign 50 subjects to the treatment condition and 50 to the control, and measure smoking frequency on a 1-5 scale. At the end of the study the researcher finds that the treatment subjects improved, with a standardized mean difference effect size of .51. Which of the following interpretations is correct? Select one: a. On a 1-5 scale, smoking frequency decreased by about a half a point b. Relative to the control group, the treatment group mean was 51% lower c. The mean difference between the treatment and control group is equivalent to about a half a standard deviation d. The control group mean was 51% larger when measured on the 1-5 scale

The mean difference between the treatment and control group is equivalent to about a half a standard deviation

Consider the bar graph below, which depicts the distribution of appropriateness ratings for texting during sex. Which of the following is most likely true? https://ccle.ucla.edu/pluginfile.php/2597873/question/questiontext/2655215/7/15735372/29.png Select one: a. The mean is lower than the median b. The mean and median are about the same c. The mean is higher than the median

The mean is higher than the median

In a normal distribution, which of the following is true? Select one: a. The mean is higher than the median b. The mean is lower than the median c. The mean is the same as the median d. The mean could be higher or lower than the median

The mean is the same as the median

Two depression researchers compute the sample mean for a popular depression questionnaire. The first researcher has a standard error of .50, and the second researcher has a standard error of .70. Which researcher obtained an estimate that is probably closer to the population mean? Select one: a. The one with the standard error of 0.70 b. The one with the standard error of 0.50 c. Both estimates should be equally close to the population mean

The one with the standard error of 0.50

A Huffington Post poll of registered voters is designed to estimate the percentage of respondents that approve of Donald Trump's performance as President Which of the following is true? Select one: a. The percentage of approving voters in the sample will be larger than the percentage in the population b. The percentage of approving voters in the sample will be smaller than the percentage in the population c. The percentage of approving voters in the sample could be larger or smaller than the percentage in the population d. The sample size will determine whether the percentage of approving voters in the sample is larger or smaller than the population

The percentage of approving voters in the sample could be larger or smaller than the percentage in the population

A psychologist studying smoking behavior in a sample of 200 smokers finds the mean number of cigarettes smoked per week is 8 with a standard error of .20. Which of the following interpretations correct for the standard error? Select one: a. The sample mean based on 200 participants should differ from the true population mean by .20, on average b. The average difference between a smoking score and the sample mean is .20 c. If the researcher took another sample of any size, the mean should change by .20, on average d. A sample of N = 200 participants should produce scores that differ from the mean by .20, on average

The sample mean based on 200 participants should differ from the true population mean by .20, on average

A psychologist studying aggressive behavior in a sample of 30 children finds the average number of aggressive acts during a play period is 6 with a standard error of .50. Which of the following interpretations correct for the standard error? Select one: a. If the researcher took another sample of children, the mean should change by .50, on average b. The average difference between an aggression score and the sample mean is .50 c. The sample mean based on 30 children should differ from the true population mean by .50, on average d. A sample of N = 30 children should produce scores that differ from the mean by .50, on average

The sample mean based on 30 children should differ from the true population mean by .50, on average

A psychologist studying post-partum depression administered a questionnaire to a sample of 100 new mothers and obtained a mean depression score of 22 with a standard error of the mean equal to .60. Which of the following interpretations is correct for the standard error? Select one: a. A sample mean based on N = 200 should differ from the population mean by .60, on average b. The sample mean based on N = 100 should differ from the true population mean by .60, on average c. The average difference between a depression score and the mean is .60 d. If the researcher took another sample of any size, the mean should change by .60, on average

The sample mean based on N = 100 should differ from the true population mean by .60, on average

A social psychologist is trying to estimate the average tipping behavior in the population of restaurant patrons. She collects data from a sample of 20 participants and finds that the mean is 24% with a standard error of .50. Which of the following is true about the standard error value? Select one: a. The sample mean based on N = 20 should differ from the true population mean tip by .50, on average b. If the researcher took another sample of any size, the tipping mean should change by .50, on average c. The average difference between a person's tipping value and the mean is .50 d. This particular sample has an estimate that differs from the true population mean by .50

The sample mean based on N = 20 should differ from the true population mean tip by .50, on average

A clinical psychologist is trying to estimate the average number of alcoholic drinks per week in the population of college students. She collects data from a sample of 20 participants and finds that the mean is 5 with a standard error of .20. Which of the following is true about the standard error value? Select one: a. If the researcher took another sample of any size, the mean number of drinks should change by .20, on average b. The sample mean based on N = 20 students should differ from the true population mean by .20, on average c. This particular sample has an estimate that differs from the true population mean by .20 d. The average difference between a person's drinking value and the mean is .20

The sample mean based on N = 20 students should differ from the true population mean by .20, on average

A sample of IQ scores has a mean of 101 and a standard deviation of 14. The sample standard deviation was computed using a formula with N-1 (the degrees of freedom) rather than N in the denominator. Which of the following is true regarding the N-1 value in the standard deviation formula? Select one: a. The standard deviation = 14 value is a more accurate estimate of the standard deviation of the full population of IQ scores b. The mean = 101 value is a more accurate estimate of the mean of the full population of IQ scores c. We use N-1 to correct the equation because we must square scores to eliminate negative signs d. N-1 in the denominator has no impact on the accuracy of the mean or standard deviation of the IQ scores

The standard deviation = 14 value is a more accurate estimate of the standard deviation of the full population of IQ scores

A sample of depression scores has a mean of 20 and a standard deviation of 5. The sample standard deviation was computed using a formula with N-1 (the degrees of freedom) in the denominator. Which of the following is true regarding the N-1 value in the standard deviation formula? Select one: a. N-1 in the denominator has no impact on the accuracy of the mean or standard deviation of depression scores b. We use N-1 to correct the equation because we must square scores to eliminate negative signs c. The mean = 20 value is a more accurate estimate of the mean of the full population of depression scores d. The standard deviation = 5 value is a more accurate approximation of the standard deviation of depression scores in the full population

The standard deviation = 5 value is a more accurate approximation of the standard deviation of depression scores in the full population

In what situation will the sample mean be closest to the population mean? Select one: a. The population size is small b. The population size is large c. The standard error is small d. The standard error is large

The standard error is small

A psychologist studying post-partum depression administered a questionnaire to a sample of 100 new mothers and obtained a mean depression score of 22 with a standard deviation of 4. The standard error of the mean is .40. All other things being equal, what will happen to the standard error if the sample size was increased to 200? Select one: a. The standard error will increase b. The standard error will remain the same c. The standard error will decrease

The standard error will decrease

A psychologist studying post-partum depression administered a questionnaire to a sample of 100 new mothers and obtained a mean depression score of 22 with a standard deviation of 4. The standard error of the mean is .40. All other things being equal, what will happen to the standard error if the standard deviation is reduced to 2? Select one: a. The standard error will decrease b. The standard error will increase c. The standard error will remain the same

The standard error will decrease

A psychologist studying post-partum depression administered a questionnaire to a sample of 100 new mothers and obtained a mean depression score of 22 with a standard deviation of 4. The standard error of the mean is .40. All other things being equal, what will happen to the standard error if the sample size is reduced to 50? Select one: a. The standard error will decrease b. The standard error will increase c. The standard error will remain the same

The standard error will increase

A test preparation company reports that, after taking their GRE preparation class, student scores increased by a magnitude that is equivalent to .25 standard deviation units. Which of the following is true? Select one: a. The test prep class produced a significant improvement in scores b. The test prep class produced virtually no improvement in scores c. The test prep class produced a relatively small improvement in scores d. The test prep class produced a large improvement in scores e. The test prep class produced a non-significant improvement in scores

The test prep class produced a relatively small improvement in scores

In a positively skewed distribution, a student obtains a test score below the mean. What do we know about this student's z-score? Select one: a. The z-score is zero b. The z-score could be positive or negative c. The z-score is negative d. The z-score is positive

The z-score is negative

A clinical researcher estimates the rate of clinical depression among new mothers at 15%, with a confidence interval ranging between 13% and 17%. Which of the following is true? Select one: a. There is a 95% probability that the interval from 13% and 17% contains the true percentage of depressed mothers in the population b. 95% of all random samples would give estimates between 13% and 17% c. On average, random samples of mothers will give estimates that are 2% from the true percentage of depressed mothers in the population d. The true percentage of depressed mothers definitely falls between 13% and 17%

There is a 95% probability that the interval from 13% and 17% contains the true percentage of depressed mothers in the population

Using a 0-10 scale, a health psychologist reports that the sample mean pain rating is 7 with a 95% confidence interval ranging between 6.5 to 7.5. Which of the following is true? Select one: a. The true pain mean in the population definitely falls between 6.5 and 7.5 b. On average, random samples of participants will give estimates that are .5 points from the true pain mean in the population c. There is a 95% probability that the interval from 6.5 and 7.5 contains the true mean pain rating in the population d. 95% of all random samples would give pain means between 6.5 and 7.5

There is a 95% probability that the interval from 6.5 and 7.5 contains the true mean pain rating in the population

Using a popular depression scale, a clinical researcher estimates the mean depression score among new mothers at 19. Which of the following statements illustrates a confidence interval? Select one: a. 95% of the true population means fall between 17 and 21 b. 95% of random samples will give sample means between 17 and 21 c. There is a 95% probability that the range between 17 and 21 contains the true depression mean in the population of new mothers d. Across many random samples, the standard deviation of the estimates is 5%

There is a 95% probability that the range between 17 and 21 contains the true depression mean in the population of new mothers

A clinical researcher estimates the mean depression score among new mothers as 19, and the corresponding confidence interval ranges from 17 to 21. Which of the following interpretations is true about the confidence interval. Select one: a. 95% of all random samples would yield sample means ranging from 17 to 21 b. The true mean in the population of new mothers must fall somewhere between 17 to 21 c. If the researcher repeated the study with a new sample, there is a 95% chance that the new sample mean would fall between 17 to 21 d. There is a 95% probability that the range from 17 to 21 includes the true depression mean in the population of new mothers

There is a 95% probability that the range from 17 to 21 includes the true depression mean in the population of new mothers

A clinical researcher estimates the rate of clinical depression among new mothers at 15%, and the corresponding confidence interval ranges from 7% to 23%. Which of the following interpretations is true about the confidence interval. Select one: a. The true proportion of depressed mothers in the population must fall somewhere between 7% to 23% b. 95% of all random samples would yield estimates ranging from 7% to 23% c. There is a 95% probability that the range from 7% to 23% includes the true percentage of mothers in the population d. If the researcher repeated the study with a new sample, there is a 95% chance that the new estimate would fall between 7% to 23%

There is a 95% probability that the range from 7% to 23% includes the true percentage of mothers in the population

Which of the following variables is measured on an interval (approximately continuous) scale? Select one: a. Time (in minutes) spent on social media per day b. Political affiliation c. Self-reported health (poor, fair, good, excellent) d. Treatment assignment (treatment vs. control)

Time (in minutes) spent on social media per day

Suppose that we obtained the percentage of Hillary Clinton voters from 100 different polls of size N = 200 and constructed a histogram of the 100 estimates. Next, suppose that we obtained the percentage of Hillary Clinton voters from 100 different polls of size N = 1000 and graphed the 100 estimates (i.e., made a sampling distribution). True or false? The mean (center) of the two sampling distributions will be identical. Select one: a. False b. True

True

A researcher reports that the average squared distance from the scores to the mean is 9 points. Which measure of variability is he reporting? Select one: a. Variance b. Range c. Standard deviation

Variance

Which of the following variables is measured on a nominal scale? Select one: a. IQ b. Education level( less than HS, HS grad, some college, college grad) c. Income (<30K, 30K-50K, 50K-80K, 80K or higher) d. Ethnicity

ethnicity

A researcher studying post-partum depression wants to report the central tendency for her depression scale score. In most situations, which measure of central tendency is most desirable? Select one: a. Mean b. Mode c. Median

mean

Which of the following variables is measured on a nominal scale? Select one: a. Political affiliation b. Number of children in a family c. Minutes spent exercising per week d. Self-reported health (poor, fair, good, excellent)

political affiliation