Exam 1 PSYCH 311 Final Study Guide

33. Which of the following best describes an independent variable? A) the sample variable B) the measured behavior C) the manipulated variable D) the population variable

C

1. An education counselor records the number of high school graduates enrolled in community colleges, four-year colleges, and universities. What scale of measurement is the type of college? A) nominal B) ordinal C) interval D) ratio

A

15. Which of the following is the best explanation for why the standard deviation is almost always reported with the mean? A) The standard deviation measures the spread of scores from the mean, so it is important to know both the mean and the standard deviation. B) The standard deviation is also a measure of central tendency, so it is important to report this value with the mean. C) The mean and standard deviation estimate basically the same thing, so these values are typically reported together. D) This is not true; the standard deviation is rarely reported with the mean.

A

16. A researcher decides to split scores on an exam into quartiles. She determines that a score of 64 is at the 25th percentile, a score of 74 is at the 50th percentile, and a score of 80 is at the 75th percentile. What is the interquartile range (IQR) for these data? A) 16 B) 10 C) 6 D) There is not enough information to answer this question.

A

20. A researcher records the time (in seconds) that participants arrive late for a scheduled research study. Assuming these data are normally distributed, which measure of central tendency is most appropriate to describe these data? A) mean B) median C) mode D) range

A

24. The correct order of operations in math, is: A) parentheses, roots, exponents, multiplication, division, addition, and subtraction B) addition, subtraction, parentheses, roots, exponents, multiplication, and division C) parentheses, roots, multiplication, division, addition, subtraction, and exponents D) exponents, multiplication, division, parentheses, roots, addition, and subtraction

A

35. Fill in the missing values for A and B in this frequency distribution table: Intervals Frequency 6.0-6.6 12 5.3-5.9 7 4.6-5.2 B 3.9-4.5 10 A-3.8 8 50 A) A = 3.2, B = 13 B) A = 3.1, B = 14 C) A = 3.3, B = 13 D) There is not enough information to complete this table.

A

36. Who should you contact first if you have a question about ANY class policy (e.g., missed exams)? A) Your graduate TA B) Your professor C) The chair of the psychology department D) The president of WSU

A

40. A researcher measures the number of trials it takes two samples of participants to master a new task. In both samples, SS = 240. Sample A consisted of 12 participants and Sample B consisted of 18 participants. Which sample is associated with the largest variance? A) Sample A B) Sample B C) Both samples have the same variance. D) There is not enough information to answer this question.

A

49. Procedures that allow researchers to infer or generalize observations made with samples to the larger population from which they were selected best describes A) inferential statistics B) sample statistics C) descriptive statistics D) population parameters

A

51. Researchers measure data in a ________ to learn more about individuals in the larger _______ of interest. A) sample; population B) statistic; inference C) population; sample D) inference; statistic

A

6. A researcher records 17 scores. What is the median position of these scores? A) the 9th score in numeric order B) the average of the 9th and 10th scores in numeric order C) the average of the 8th and 9th scores in numeric order D) It's not possible to know this without the raw scores.

A

7. A researcher records the following data for the number of dreams recalled during a night of sleep for 10 college students: 3, 2, 4, 4, 3, 1, 1, 0, 2, and 0. Is the mean equal to the median in this example? A) Yes. B) No; the median is larger than the mean. C) No; the mean is larger than the median. D) There is not enough information to answer this question.

A

10. The "empirical rule" states that A) all scores will fall within 3 standard deviations of the mean. B) at least 68% of scores fall within 1 standard deviation of the mean. C) at least 95% of scores fall within 2 standard deviation of the mean. D) both b and c

D

11. Which of the following will decrease the value of the mean? A) deleting a score below the mean B) adding a score below the mean C) adding a score exactly equal to the mean D) none of the above

B

12. To construct a pie chart, first distribute the data as A) cumulative percentages B) relative percentages C) cumulative frequencies D) cumulative relative percentages

B

13. A researcher records the time in seconds it takes a sample of participants to walk alone through a dark portion of campus. The researcher computes SS = 1,000. Assuming that a sample of 11 participants was observed in this study, what is the standard deviation for these data? A) 1 seconds B) 10 seconds C) 100 seconds D) 1000 seconds

B

17. The degrees of freedom for the sample variance A) are equal to the sample size B) are equal to the sample size minus one C) can vary between - and + D) both B and C

B

22. A researcher records the time it takes to complete a memory task in a sample of 25 participants. He finds that the average participant completed the test in 43 seconds. The average time to complete this task is called a(n) A) population parameter B) sample statistic C) inferential statistic D) time trial

B

25. Measures of variability can range in value from A) - to + B) 0 to + C) It depends on whether the variability is positive or negative. D) It depends on the value of the mean for a given distribution.

B

26. The range of scores in each interval of a grouped frequency distribution is called the A) simple frequency B) interval width C) real range D) grouped data

B

3. A researcher reports that "the average shopper in the sample (n = 12) purchased $65.00 worth of items ( = $65.00) during a busy shopping day." What mistake was made is this citation? A) None; this citation is written appropriately. B) The sample mean is written using the wrong notation. C) The sample size is written using the wrong notation. D) both B and C

B

30. What terms refer to each of the following measures, respectively: mean, median, and mode. A) middle, most, and average B) average, middle, and most C) average, most, and middle D) most, average, and middle

B

32. When can I break the rules for the class that are stated in the syllabus and get special treatment that's not available to other students? A) If you are sick. B) Never, because all of the policies (including opportunities for dropped exams) were planned to make life easier for all students, that is, with the expectation that many students get sick, have personal emergencies or tragedies. C) If you are really trying hard. D) If you need to attend a funeral or wedding

B

37. The ________ is the middle value in a distribution of scores that are listed in numeric order. A) mean B) median C) mode D) range

B

44. State the four scales of measurement in order from least informative to most informative. A) ordinal, nominal, interval, ratio B) nominal, ordinal, interval, ratio C) nominal, ordinal, ratio, interval D) ordinal, nominal, ratio, interval

B

31. The size of a population is symbolized as ________, whereas the size of a sample is symbolized as ________. A) ; M B) M; C) n; N D) N; n

D

46. What is the description of SS (Sum of squares) in words? That is, what does it stand for? A) Sum or deviations of scores from the mean. B) Sum of squared deviations of scores from the mean. C) Sum of the square roots of scores. D) Sum of the squared scores divided by the mean.

B

47. In the stem-and-leaf display, each number to the right of the vertical line is referred to as a ________; the numbers to the left of the vertical line are called the ________. A) stem; leaf B) leaf; stem C) digit; place D) place; digit

B

48. A researcher measures the amount of coffee consumed by college students while studying during the final exam week. In her study, she found that students drink 2.3±0.8 (M±SD) cups of coffee per study session. Assuming the data are normally distributed, which of the following is the most appropriate conclusion? A) The average student drinks less than 2.3 cups of coffee per study session. B) Most students drink between 1.5 and 3.1 cups of coffee per study session. C) Most students drink between 2.3 and 3.9 cups of coffee per study session. D) Most students drink between 0.7 and 2.3 cups of coffee per study session.

B

5. Regardless of the number of scores in a distribution, the range only includes ___ score(s) in its calculation. A) one B) two C) at most two D) the average

B

52. When SS = 100 and N = 25, the population standard deviation is equal to __ A) 10 B) 2 C) 4 D) There is not enough information to determine the population standard deviation.

B

8. A researcher selects a sample of 24 participants and has them complete a survey on dating preferences. In this example, what are the degrees of freedom for sample variance and what does this figure represent? A) df = 24; it represents the number of scores that are free to vary in a sample. B) df = 23; it represents the number of scores that are free to vary in a sample. C) df = 23; dividing SS by df makes the sample variance a biased estimator of the population variance. D) df = 24; dividing SS by df makes the sample variance an unbiased estimator of the population variance.

B

9. Which of the following best describes a dependent variable? A) the sample variable B) the measured behavior C) the manipulated variable D) the population variable

B

14. A researcher records the sound (in decibels) during a series of lessons taught by a substitute teacher at a local elementary school. In his study, he found that the sound was 80±6 (M±SD) decibels. Assuming the data are normally distributed, which of the following is an appropriate conclusion? A) 68% of classes were between 68 and 80 decibels. B) 5% of classes were louder than 68 decibels. C) 95% of classes were between 68 and 92 decibels. D) all of the above

C

18. State the problem with this simple frequency distribution. Intervals Frequency 8-10 4 6-8 7 4-6 3 2-4 6 0-2 9 A) The interval width is too small. B) The interval width is unequal. C) The class intervals overlap. D) The number of intervals is too small.

C

19. You are interested in measuring the construct, reinforcement. Which of the following measures for this construct is quantitative and continuous? A) the number of rewards received B) the type of reward (food, money) C) the size of a reward in grams D) the rating of a reward on a scale from 1 (not reinforcing) to 7 (very reinforcing)

C

2. A researcher records the following data: 4, 4, 4, 4, and 3. How would you describe the variability of these data? A) It is equal to zero because scores are approximately the same. B) It is negative because 3 is less than the other scores in the distribution. C) It is very small (close to 0) because scores are approximately the same. D) It is very large (much greater than 0) because 3 is an outlier in the data.

C

21. Each of the following is an example of quantitative data, except A) weight in ounces B) income in dollars C) political affiliation D) age in years

C

23. A researcher asks participants to estimate the height (in inches) of a statue that was in a waiting area. The researcher records the following estimates: 40, 46, 30, 50, and 34. If the researcher removes the estimate of 40 (say, due to an experimenter error), then the value of the mean will____ (Hint: Calculate the mean first!) A) decrease B) increase C) remain the same D) become negative

C

27. A professor grades 120 research papers and reports that the average score was an 80%. What do we know about the sum of the differences of these 120 scores from their mean of 80%? A) The sum of the differences is minimal. B) The sum of the differences is 80%, the same as the mean. C) The sum of the differences is equal to zero. D) It is impossible to know without knowing each of the 120 scores.

C

28. The following is a simple frequency distribution table. If we convert this frequency distribution to relative percentages, which of the following gives the corresponding percentages in each interval listed from the top down. Intervals Frequency 44-46 6 41-43 4 38-40 5 35-37 10 32-34 5 30 A) 20%, 33%, 50%, 67%, 100% B) 0.2, 0.13, 0.17, 0.33, 0.17 C) 20%, 13%, 17%, 33%, 17% D) 6, 10, 15, 25, 30

C

29. When would a researcher calculate a population mean? A) when data are measured for of a portion of individuals from a population B) when the sample mean is not available C) when data are measured for all members of a population D) when it is not possible to measure all data in a population

C

34. A researcher wants to determine how many participants will take less than 24 seconds to complete a cognitive performance task. If he constructs a frequency distribution for these data, what type of distribution would be most appropriate to answer his question? A) a simple frequency distribution B) a relative frequency distribution C) a cumulative frequency distribution from the bottom up D) a cumulative frequency distribution from the top down

C

38. The use of tables and graphs to summarize data is an example of A) inferential statistics B) interpretation C) descriptive statistics D) generalization

C

50. A cumulative percentage summary that indicates the percentage of scores at or below a given value is called a A) relative percentage B) relative frequency C) percentile rank D) cumulative frequency

C

39. A therapist observes that spouses are more likely to forgive their partners for lying to them if they find out the truth from their spouse and not a third party. In this example, the dependent variable is A) the number of partners B) the spouse C) lying D) forgiveness

D

4. The sample variance is: A) an unbiased estimator of the population variance B) associated with n - 1 degrees of freedom C) computed by dividing SS by df D) all of the above

D

41. What is the percentile point at the 80th percentile in the following distribution? Frequency Percentile Rank 9-11 100% 6-8 80% 3-5 40% 0-2 20% A) 2 B) 6 C) 7 D) 8

D

42. A researcher selects a sample of 6 males and 11 females. She asks participants to rate the likelihood they would do female-stereotyped jobs (such as nursing or school teaching) on a scale from 1 = not likely at all to 5 = very likely. Men indicated that they would be less likely to do these jobs (M = 2.1) compared with women (M = 4.3). What is the weighted mean for this entire sample of 17 participants? A) 2.1 B) 4.3 C) 3.2 D) 3.5

D

43. Which of the following is true about the computational formula for variance? A) The computational formula will always produce the same solution as the definitional formula (give or take rounding errors). B) It is a short-cut method for calculating variance when the population or sample size is large. C) It is derived mathematically from the definitional formula. D) all of the above

D

45. A researcher compares the amount of college debt (in dollars) that undergraduate students incur up to their four-year degree. College debt is on what scale of measurement? A) nominal B) ordinal C) interval D) ratio

D