WBWK 2

For each part, indicate under which of the seven critical components the indicated information should be classified (b) For a study that involved the explanatory variables SEX, the fact that all the women in the study were under the age of 30 while the men in the study were all over the age of 40. A. Component 6: Extraneous differences. B. Component 1: Source. C. Component 4: Measurements. D. Component 5: Setting. E. Component 2: Researchers.

A. Component 6: Extraneous differences.

(a) A study was conducted in which the explanatory variable was SEX (male or female). Based on this information, the study MUST have been A. an observational study. B. an experiment. C. a case-control study. D. a matched-pairs design. E. None of the above.

A. an observational study.

For each part, indicate under which of the seven critical components the indicated information should be classified (c) The fact that a study was originally published in The New England Journal of Medicine. A. Component 6: Extraneous differences. B. Component 1: Source. C. Component 5: Setting. D. Component 2: Researchers. E. Component 4: Measurements.

B. Component 1: Source.

1. (b) A professor records the values of several variables for each student in his class. These include the variables listed below. Which of these variables is categorical? A. The total number of points earned in the class B. The number of lectures the student missed. C. Grade for the course (A, B, C, D, or F). D. Score on the final exam (out of 150 points). E. None of the above.

C. Grade for the course (A, B, C, D, or F).

1. (a) A survey records many variables of interest to the researchers conducting the survey. Below are some of the variables from a survey conducted by the U.S. Postal Service. Which of these variables is categorical? A. Number of people, both adults and children, living in the household. B. Age of respondent. C. Total household income, before taxes, last year. D. County of residence. E. None of the above.

D. County of residence.

2. (b) Which of the following is an example of an interval variable. A. The number of days last year the Columbia Public Schools were closed due to inclimate weather. B. The amount of rain (in inches) that fell last night in Columbia. C. The number of earthquakes that occurred last year that affected California. D. The high temperature yesterday in Columbia (measured in degrees Fahrenheit). E. None of the above.

D. The high temperature yesterday in Columbia (measured in degrees Fahrenheit).

For each part, indicate under which of the seven critical components the indicated information should be classified. (a) The fact that a study was paid for by a grant from the National Institutes of Health. A. Component 6: Extraneous differences. B. Component 4: Measurements. C. Component 5: Setting. D. Component 2: Researchers. E. Component 1: Source.

E. Component 1: Source.

Three separate random samples of students (one sample selected from each of three different colleges) were selected in order to estimate the population percentage of students at each college who are sophomores. Sample 2: 75 students were selected from among all those attending college number 2 and 10 of them were found to be sophomores. (b) If sample 2 is used to estimate the population percentage of students at college number 2 who are sophomores, what is the margin of error? Enter margin of error as a percentage rounded to one decimal place: ? percent.

11.5%

Three separate random samples of students (one sample selected from each of three different colleges) were selected in order to estimate the population percentage of students at each college who are sophomores. Sample 3: The sample from college number 3 showed that 30% of students were sophomores with a margin of error of (plus or minus) 10%. (c) If sample 3 is used to estimate the population percentage of students at college number 3 who are sophomores, then an interval that "almost certainly" contains the true population percentage is: ? percent to ? percent. (Enter lower-bound in first blank and upper-bound in second blank.)

20% & 40%

Three separate random samples of students (one sample selected from each of three different colleges) were selected in order to estimate the population percentage of students at each college who are sophomores. Sample 1: 140 students were selected from among all those attending college number 1 and 30 of them were found to be sophomores. (a) If sample 1 is used to estimate the population percentage of students at college number 1 who are sophomores, what is the margin of error? Enter the margin of error as a percentage rounded to one decimal place:

8.5 percent

(b) A study was conducted in order to compare SALARIES of men and women who work as professional actuaries. The response variable was A. SEX (man or woman). B. SALARY. C. Whether or not the subject was an actuary. D. Whether or not the subject owns a home. E. All of the above.

B. SALARY.

A small local telephone company serves a total of 2,000 phone lines distributed among 1,800 customers. (Some customers have only one phone line while others have multiple phone lines.) Of these 2,000 phone lines, 1,500 are residential and 500 are business. The phone company has available to it the following lists: a list of the 2,000 phone lines; a list of the 1,800 customers; a list of the 1,500 residential phone lines; and a list of the 500 business phone lines. For each question, identify the sampling plan used to select the sample of phone lines. (b) The company randomly selects 15 phone lines from the list of residential phone lines and 15 phone lines from the list of business phone lines. A. Volunteer sample. B. Stratified random sample. C. Simple random sample. D. Cluster sample. E. Systematic sample.

B. Stratified random sample.

6.(b) A study was conducted in order to compare SAT scores for students who attend Mizzou and students who attend Vanderbilt. The explanatory variable was A. Whether or not a subject owns a car. B. UNIVERSITY (Mizzou or Vanderbilt). C. SAT score. D. the AGE of respondent. E. None of the above.

B. UNIVERSITY (Mizzou or Vanderbilt).

(2 pts) A study was conducted to determine if a new drug for treating depression is more effective than an existing drug. One hundred subjects who suffer from servere depression participated. Fifty were selected at random and were given the new drug and the other 50 were given the existing drug. A psychiatrist evaluated the symptoms of all subjects after four weeks and determined whether or not each subject's condition had improved. (b) The response variable in this study was A. DRUG (new or existing). B. whether or not the subject's condition improved. C. the AGES of the subjects. D. the number of subjects who were studied. E. whether the psychiatrist was male or female.

B. whether or not the subject's condition improved.

1. (c) A description of different houses on the market includes several variables. Which of these is a measurement variable? A. The exterior paint colors. B. The street name. C. The average monthly electric bill for the past year. D. The school district. E. None of the above.

C. The average monthly electric bill for the past year.

2. (c) For houses currently for sale in a certain community several variables were measured. Which of these variables would be classified as categorical? A. The distance from the house to the nearest interstate highway. B. The asking price. C. Whether or not the house contains over 2,500 square feet of living space. D. Total cost of heating for the previous calendar year (in dollars). E. None of the above.

C. Whether or not the house contains over 2,500 square feet of living space.

8. (a) Experimental designs that use either two matched individuals or the same individual to receive each of two treatments are called A. retrospective studies. B. case-control studies. C. matched-pair designs. D. placebo studies. E. All of the above.

C. matched-pair designs.

1. (d) A survey regarding television watching recorded several variables for a sample of local residents. Which of these variables are categorical? A. The number of television sets the respondent owns. B. The age of the respondent, in years. C. The amount of time, in hours, that the respondent watched television last week. D. The name of the show, if any, that the respondent was watching at 7 p.m. last Thursday. E. All of the above.

D. The name of the show, if any, that the respondent was watching at 7 p.m. last Thursday.

For each part, indicate under which of the seven critical components the indicated information should be classified (d) The fact that a survey regarding the extent to which local government is prepared for a weather emergency was conducted immediately following a major snowstorm. A. Component 4: Measurements. B. Component 6: Extraneous differences. C. Component 1: Source. D. Component 2: Researchers. E. Component 5: Setting.

E. Component 5: Setting.

A small local telephone company serves a total of 2,000 phone lines distributed among 1,800 customers. (Some customers have only one phone line while others have multiple phone lines.) Of these 2,000 phone lines, 1,500 are residential and 500 are business. The phone company has available to it the following lists: a list of the 2,000 phone lines; a list of the 1,800 customers; a list of the 1,500 residential phone lines; and a list of the 500 business phone lines. For each question, identify the sampling plan used to select the sample of phone lines. (d) The company randomly selects 100 phone lines from the list of all phone lines. A. Volunteer sample. B. Cluster sample. C. Systematic sample. D. Stratified random sample. E. Simple random sample.

E. Simple random sample.

A small local telephone company serves a total of 2,000 phone lines distributed among 1,800 customers. (Some customers have only one phone line while others have multiple phone lines.) Of these 2,000 phone lines, 1,500 are residential and 500 are business. The phone company has available to it the following lists: a list of the 2,000 phone lines; a list of the 1,800 customers; a list of the 1,500 residential phone lines; and a list of the 500 business phone lines. For each question, identify the sampling plan used to select the sample of phone lines. (c) The company selects the phone lines that are listed 100th, 200th, 300th, etc., from the list of all phone lines. A. Simple random sample. B. Stratified random sample. C. Volunteer sample. D. Cluster sample. E. Systematic sample.

E. Systematic sample.

2. (a) STUDENT NUMBER, as applied to Mizzou students, is which kind of variable? A. categorical B. discrete C. measurement D. continuous E. All of the above.

A. categorical

8. (b) A study involved the response variable TIME spent talking on the phone during one week and the explanatory variable SEX (male or female). The study concluded that, for those under 30, women tended to spend more time talking on the phone than men but, for those 30 and older, men tended to spend more time talking on the phone than women. This information suggests that the variables SEX (male or female) and AGE CATEGORY (under 30; 30 and older) A. interact. B. are continuous measurement variables. C. are confounded. D. are ratio variables. E. None of the above.

A. interact.

9. In a study concerning eating habits, two types of movies (action and comedy) were shown to a group of people. (The explanatory variable is TYPE OF MOVIE.) During each movie, crackers were available in a bowl and the investigators compared the number of crackers eaten by the subjects while watching the different TYPES OF MOVIES. An action movie was shown at 8 A.M. and a comedy was shown at 11 A.M. (The same group of subjects watched both movies on the same day.) It was found that during comedy, more crackers were eaten than during the action movie. The investigators concluded that type of movie affects appetite. (a) The response variable in this study is A. the number of crackers eaten. B. TYPE OF MOVIE (action or comedy). C. the TIME the movie was shown (8 A.M. or 11 A.M.). D. the bowls.

A. the number of crackers eaten.

In a study concerning eating habits, two types of movies (action and comedy) were shown to a group of people. (The explanatory variable is TYPE OF MOVIE.) During each movie, crackers were available in a bowl and the investigators compared the number of crackers eaten by the subjects while watching the different TYPES OF MOVIES. An action movie was shown at 8 A.M. and a comedy was shown at 11 A.M. (The same group of subjects watched both movies on the same day.) It was found that during comedy, more crackers were eaten than during the action movie. The investigators concluded that type of movie affects appetite (c) This is an example of a A. simple random sample. B. matched pairs design. C. volunteer sample. D. case-control study. E. None of the above.

B. matched pairs design.

9. In a study concerning eating habits, two types of movies (action and comedy) were shown to a group of people. (The explanatory variable is TYPE OF MOVIE.) During each movie, crackers were available in a bowl and the investigators compared the number of crackers eaten by the subjects while watching the different TYPES OF MOVIES. An action movie was shown at 8 A.M. and a comedy was shown at 11 A.M. (The same group of subjects watched both movies on the same day.) It was found that during comedy, more crackers were eaten than during the action movie. The investigators concluded that type of movie affects appetite. (b) A confounding variables whose presence may make the investigator's conclusion invalid is A. the bowls. B. the TIME the movie was shown (8 A.M. or 11 A.M.). C. TYPE OF MOVIE (action or comedy). D. the number of crackers eaten.

B. the TIME the movie was shown (8 A.M. or 11 A.M.).

A small local telephone company serves a total of 2,000 phone lines distributed among 1,800 customers. (Some customers have only one phone line while others have multiple phone lines.) Of these 2,000 phone lines, 1,500 are residential and 500 are business. The phone company has available to it the following lists: a list of the 2,000 phone lines; a list of the 1,800 customers; a list of the 1,500 residential phone lines; and a list of the 500 business phone lines. For each question, identify the sampling plan used to select the sample of phone lines. (a) The company randomly selects 25 customers and includes every phone line that belongs to one of the selected customers in its sample. A. Systematic sample. B. Simple random sample. C. Cluster sample. D. Stratified random sample. E. Volunteer sample.

C. Cluster sample.

6. (a) A study involved the response variable TASTE RATING (0 to 10) and the explanatory variable TYPE OF BEVERAGE (carbonated or non-carbonated). Further analysis revealed the carbonated beverage used in the study was sweetened with aspartame while the non-carbonated beverage used in the study was sweetened with sugar. From the information provided about this study, the variables TYPE OF BEVERAGE (carbonated or non-carbonated) and SWEETENER (aspartame or sugar) A. interact. B. are measurement variables. C. are confounded. D. are interval variables. E. All of the above.

C. are confounded.

10. A study was conducted to determine if a new drug for treating depression is more effective than an existing drug. One hundred subjects who suffer from servere depression participated. Fifty were selected at random and were given the new drug and the other 50 were given the existing drug. A psychiatrist evaluated the symptoms of all subjects after four weeks and determined whether or not each subject's condition had improved. (a) The explanatory variable in this study was A. the AGE of the subjects. B. whether or not the subject's condition improved. C. the amount of TIME the psychiatrist spent evaluating each patient. D. DRUG (new or existing). E. whether the psychiatrist was male or female.

D. DRUG (new or existing).

2. (d) A study of recent college graduates recorded the SEX (male or female) and total COLLEGE DEBT (measured to the nearest dollar) for sample of 10,000 people one year after they had graduated from college. Which of the following statements is true? A. SEX is a categorical variable and COLLEGE DEBT is a continuous measurement variable. B. SEX is a measurement variable and COLLECT DEBT is a categorical variable. C. SEX and COLLEGE DEBT are both discrete measurement variables. D. SEX is a nominal variable and COLLEGE DEBT is a discrete measurement variable. E. None of the above.

D. SEX is a nominal variable and COLLEGE DEBT is a discrete measurement variable.