Understanding Statistics in the Behavioral Sciences ... - NelsonBrain

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Licensed to: groups of 10 students in each group. All students are asked to memorize a list of 15 words and are given three practice sessions, each 5 minutes long, in which to do so. Practice sessions for group 1 subjects are spaced 10 minutes apart; for group 2, 20 minutes apart; and for group 3, 30 minutes apart. All groups are given a retention test 1 hour after the last practice session. Results are recorded as the number of words correctly recalled in the test period. Mean values are computed for each group and compared. cognitive f. A sport psychologist uses visualization in promoting enhanced performance in college athletes. She is interested in evaluating the relative effectiveness of visualization alone versus visualization plus appropriate self-talk. An experiment is conducted with a college basketball team. Ten members of the team are selected. Five are assigned to a visualization alone group, and fi ve are assigned to a visualization plus self-talk group. Both techniques are designed to increase foul shooting accuracy. Each group practices its technique for 1 month. The foul shooting accuracy of each player is measured before and 1 month after beginning practice of the technique. Difference scores are computed for each player, and the means of the difference scores for each group are compared to determine the relative effectiveness of the two techniques. I/O, other g. A typing teacher believes that a different arrangement of the typing keys will promote faster typing. Twenty secretarial trainees, selected from a large business school, participate in an experiment designed to test this belief. Ten of the trainees learn to type on the conventional keyboard. The other ten are trained using the new arrangement of keys. At the end of the training period, the typing speed in words per minute of each trainee is measured. The mean typing speeds are then calculated for both groups and compared to determine whether the new arrangement has had an effect. education 7. Indicate which of the following represent a variable and which a constant: a. The number of letters in the alphabet b. The number of hours in a day c. The time at which you eat dinner d. The number of students who major in psychology at your university each year e. The number of centimeters in a meter f. The amount of sleep you get each night g. The amount you weigh h. The volume of a liter Questions and Problems 19 8. Indicate which of the following situations involve descriptive statistics and which involve inferential statistics: a. An annual stockholders’ report details the assets of the corporation. b. A history instructor tells his class the number of students who received an A on a recent exam. c. The mean of a sample set of scores is calculated to characterize the sample. d. The sample data from a poll are used to estimate the opinion of the population. e. A correlational study is conducted on a sample to determine whether educational level and income in the population are related. f. A newspaper article reports the average salaries of federal employees from data collected on all federal employees. 9. For each of the following, identify the sample and population scores: a. A social psychologist interested in drinking behavior investigates the number of drinks served in bars in a particular city on a Friday during “happy hour.” In the city, there are 213 bars. There are too many bars to monitor all of them, so she selects 20 and records the number of drinks served in them. The following are the data: 50 82 47 65 40 76 61 72 35 43 65 76 63 66 83 82 57 72 71 58 social b. To make a profi t from a restaurant that specializes in low-cost quarter-pound hamburgers, it is necessary that each hamburger served weigh very close to 0.25 pound. Accordingly, the manager of the restaurant is interested in the variability among the weights of the hamburgers served each day. On a particular day, there are 450 hamburgers served. It would take too much time to weigh all 450, so the manager decides instead to weigh just 15. The following weights in pounds were obtained: 0.25 0.27 0.25 0.26 0.35 0.27 0.22 0.32 0.38 0.29 0.22 0.28 0.27 other 0.40 0.31 Copyright 2011 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.
Licensed to: 20 C H A P T E R 1 Statistics and Scientifi c Method c. A machine that cuts steel blanks (used for making bolts) to their proper length is suspected of being unreliable. The shop supervisor decides to check the output of the machine. On the day of checking, the machine is set to produce 2-centimeter blanks. The acceptable tolerance is ±0.05 centimeter. It would take too much time to measure all 600 blanks produced in 1 day, so a representative group of 25 is selected. The following lengths in centimeters were obtained: 2.01 1.99 2.05 1.94 2.05 2.01 2.02 2.04 1.93 1.95 2.03 1.97 2.00 1.98 1.96 2.05 1.96 2.00 2.01 1.99 1.98 I/O 1.95 1.97 2.04 2.02 d. A physiological psychologist, working at Tacoma University, is interested in the resting, diastolic heart rates of all the female students attending the university. She randomly samples 30 females from the student body and records the following diastolic heart rates while the students are lying on a cot. Scores are in beats/min. 62 85 92 85 88 71 73 82 84 89 93 75 81 72 97 78 90 87 78 74 61 66 83 68 67 83 75 70 86 72 biological What Is the Truth Questions 1. Data, Data, Where Are the Data? a. Find two magazine advertisements that make truth claims about the product(s) being advertised. From a scientifi c point of view, is anything missing? Discuss. b. If anyone, even an authority, asserts that “X” is true, e.g., “global warming is mainly due to human activity,” what is necessary for the truth assertion to be adequately justifi ed from a scientifi c point of view? In your opinion, based on your reading, TV viewing or other source, is the truth assertion that global warming is mainly due to human activity adequately justifi ed from a scientifi c point of view? Discuss. 2. Authorities Are Nice, but … You are attending a lecture at your university. The lecturer is a prominent physician with an international reputation. Her fi eld of expertise is Preventive Medicine. She asserts that the main cause of heart attack and stroke is eating red meat. To justify her view, she makes several logical arguments and claims all her colleagues agree with her. If you accept her view on the basis of logic or her national prominence or because her colleagues agree with her, what method(s) of determining truth are you using? From a scientifi c point of view, is this suffi cient basis to conclude the claim is true? If not, what is missing? Discuss. 3. Data, Data, What Are the Data?—1 You are reading a book written by a social psychologist on the benefi ts of developing conversation skills on relationships. There are fi ve chapters, with each chapter describing a different conversation skill. Each chapter begins with a case study showing that when the individual learned the particular skill, his or her relationships improved. From a scientifi c point of view, are the case studies suffi cient to justify the conclusion that developing the conversation skills presented in the book will improve relationships? Discuss. Copyright 2011 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.
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