PSYCH 11 CHAPTER 1 PROBLEM SETS

1.11. There are uncontrolled extraneous variables in the study described here. Name as many as you can. Begin by identifying the dependent and independent variables. An investigator concluded that statistics Textbook A was better than Textbook B, after comparing two statistics classes. One class, which met MWF at 10:00 A.M., used Textbook A and was taught by Professor X. The other class, which met for 3 hours on Wednesday evening, used Textbook B and was taught by Professor Y. At the end of the term, all students took the same comprehensive test. The mean score for the Textbook A students was higher than the mean score for the Textbook B students.

1.11 Besides differing in the textbook used, the two classes differed in (1) the professor, one of whom might be a better teacher; (2) the time the class met; and (3) the length of the class period. A 10:00 A.M. class probably has younger students who have fewer outside commitments. Students probably concentrate less during a 3-hour class than they do in three 1-hour classes. Any of these extraneous variables might be responsible for the difference in scores. Also, the investigator needs assurance that the comprehensive test was appropriate for both textbooks.

What was that easy-to-remember date that started the history of our statistics tour?

1900

1.12. In philosophy, the study of the nature of knowledge is called ________.

Epistemology

1.4. Write a paragraph that gives the definitions of population, sample, parameter, and statistic and the relationships among them.

Many paragraphs can qualify as good answers to this question. Your paragraph should include variations of these definitions: Population: a defined set of scores that is of interest to an investigator. Sample: a subset of the population Parameter: a numerical or nominal characteristic of a population Statistic: a numerical or nominal characteristic of a sample

Name the four scales of measurement identified by S. S. Stevens.

Nominal, ordinal, interval, and ratio

Give the properties of each of the scales of measurement.

Nominal: Different numbers are assigned to different classes of things. Ordinal: Nominal properties, plus the numbers carry information about greater than and less than. Interval: Ordinal properties, plus the distance between units is equal. Ratio: Interval properties, plus a zero point that means a zero amount of the thing being measured.

The dominant approach to inferential statistics that is under attack these days is called _______________________.

Null hypothesis significance testing

1.14. Your textbook recommends a three-step approach to analyzing a data set. Summarize the steps.

Step 1 is an exploratory step that involves reading the information, descriptive statistics, and attention to differences. Step 2 involves inferential statistics and answers the question of whether the differences could be due to chance. Step 3 is a story (a paragraph) written in journal style that explains the data set.

For each number, give lower and upper limits if the variable is quantitative; write qualitative beside the others. a. 65 - seconds to work a puzzle b. 319 - identification number for intellectual disability in the American Psychiatric Association manual c. 3 - category for small cup daffodils in a flower show d. 4 - score on a high school advanced placement exam e. 81 - milligrams of aspirin

a. 64.5-65.5 b. Qualitative c. Qualitative d. 3.5-4.5 e. 80.5-81.5

1.10. Researchers who are now well known conducted the three classic studies that follow. For each study, identify the dependent variable, the independent variable, and the number and names of the levels of the independent variable. Complete items i and ii. a. Theodore Barber hypnotized 25 different people, giving each a series of suggestions. The suggestions included arm rigidity, hallucinations, color blindness, and enhanced memory. Barber counted the number of suggestions that the hypnotized participants complied with (the mean was 4.8). For another 25 people, he simply asked them to achieve the best score they could (but no hypnosis was used). This second group was given the same suggestions, and the number complied with was counted (the mean was 5.1). (See Barber, 1976.) i. Identify a nominal variable and a statistic. ii. In a sentence, describe what Barber's study shows. b. Elizabeth Loftus had participants view a film clip of a car accident. Afterward, some were asked, How fast was the car going? and others were asked, How fast was the car going when it passed the barn? (There was no barn in the film.) A week later, Loftus asked the participants, Did you see a barn? If the barn had been mentioned earlier, 17 percent said yes; if it had not been mentioned, 3 percent said yes. (See Loftus, 1979.) i. Identify a population and a parameter. ii. In a sentence, describe what Loftus's study shows. c. Stanley Schachter and Larry Gross gathered data from obese male students for about an hour in the afternoon. At the end of this time, a clock on the wall was correct (5:30 p.m.) for 20 participants, slow (5:00 p.m.) for 20 others, and fast (6:00 p.m.) for 20 Introduction 27 more. The actual time, 5:30, was the usual dinnertime for these students. While partic- ipants filled out a final questionnaire, Wheat Thins® were freely available. The weight of the crackers each student consumed was measured. The means were: 5:00 group—20 grams; 5:30 group—30 grams; 6:00 group—40 grams. (See Schachter and Gross, 1968.) i. Identify a ratio scale variable. ii. In a sentence, describe what this study shows.

a. Dependent variable: number of suggestions complied with; Independent variable: hypnosis; number of levels: two; names of levels: yes and no i. Nominal variables: hypnosis, suggestions; statistic: mean number of suggestions complied with ii. Interpretation: Barber's study show that hypnotized participants do not acquire powers greater than normal (see Barber, 1976). b. Dependent variable: answer to the question Did you see a barn?; Independent variable: mention of the barn in the question about how fast the car was going; number of levels: two; names of levels: mentioned and not mentioned i. Several answers can be correct here. The most general population answer is "people" or "people's memory." Less general is "the memory of people given misinformation about an event." One parameter is the percent of all people who say they see a barn even though no barn was in the film. ii. Interpretation: If people are given misinformation after they have witnessed an event, they sometimes incorporate the misinformation into their memory. [See Loftus' book, Eyewitness Testimony (1979), which relates this phenomenon to courts of law.] c. Dependent variable: weight (grams) of crackers consumed; Independent variable: the time shown on the clock on the wall; number of levels: three; their names: slow, correct, and fast i. Weight (grams) ii. Interpretation: Eating by obese men is affected by what time they think it is; that is, consumption by obese men does not depend entirely on internal physiological cues of hunger (see Schachter and Gross, 1968).

1.9. Undergraduate students conducted the three studies that follow. For each study identify the dependent variable, the independent variable, the number of levels of the independent variable, and the names of the levels of the independent variable. a. Becca had students in a statistics class rate a resume, telling them that the person had applied for a position that included teaching statistics at their college. The students rated the resume on a scale of 1 (not qualified) to 10 (extremely qualified). All the students received identical resumes, except that the candidate's first name was Jane on half the resumes and John on the other half. b. Michael's participants filled out the Selfism scale, which measures narcissism. (Narcissism is neurotic self-love.) In addition, students were classified as first-born, second-born, and later-born. c. Johanna had participants read a description of a crime and "Mr. Anderson," the person convicted of the crime. For some participants, Mr. Anderson was described as a janitor. For others, he was described as a vice president of a large corporation. For still others, no occupation was given. After reading the description, participants recommended a jail sentence (in months) for Mr. Anderson.

a. Dependent variable: rating of qualification; independent variable: gender; number of levels: two; names of levels: female and male b. Dependent variable: narcissism; independent variable: birth order; number of levels: three; names of levels: first, second, and later born c. Dependent variable: jail sentence; independent variable: occupation; number of levels: three; names of levels: vice president, janitor, and unspecified

1.5. Two different techniques are called statistics today. Fill in the blank with one of them. a. To reach a conclusion about an unmeasured population, use _____________ statistics. b. ___________ statistics take chance into account to reach a conclusion. c. ___________ statistics are numbers or graphs that summarize a set of data.

a. Inferential b. Inferential c. Descriptive

Identify the scale of measurement in each of the following cases. a. Geologists have a "hardness scale" for identifying different rocks, called Mohs' scale. The hardest rock (diamond) has a value of 10 and will scratch all others. The second hardest will scratch all but the diamond, and so on. Talc, with a value of 1, can be scratched by every other rock. (A fingernail, a truly handy field-test instrument, has a value between 2 and 3.) b. The volumes of three different cubes are 40, 64, and 65 cubic inches. c. Three different highways are identified by their numbers: 40, 64, and 65. d. Republicans, Democrats, Independents, and Others are identified on the voters' list with the numbers 1, 2, 3, and 4, respectively. e. The winner of the Miss America contest was Miss New York; the two runners-up were Miss Ohio and Miss California.23 22 This book's index is unusually extensive. If you make margin notes, they will help too. 23 Contest winners have come most frequently from these states, which have had six winners each. 26 Chapter 1 f. The prices of the three items are $3.00, $10.00, and $12.00. g. She earned three degrees: B.A., M.S., and Ph.D.

a. Ordinal b. Ratio c. Nominal d. Nominal e. Ordinal f. Ratio g. Ordinal

1.13. a. The two approaches to epistemology identified in the text are _______ and _______. b. Statistics has its roots in ______.

a. Reason (or rationalism) and experience (or empiricism) b. Reason (or rationalism)