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Name: __________________ Class: Date: _____________ 1 For each of the following, indicate the level of the variable of interest. a. Opinion about a new tax law (favor or oppose). _________ b. Letter grade in a statistics course (A, B, and so on). _________ c. Whether the person believes in love at first sight. _________ d. Student rating of teacher effectiveness on a 7 _________ point scale where 1 = not at all effective and 7 = extremely effective. 2 To answer the following questions, researchers would need to measure two variables for each experimental unit in the study. In each case specify: 1) The experimental unit 2) Any variables that are nominal or ordinal. If no variables are measured at these levels type "None" as your answer. 3) Any variables that are quantitative. If there are no quantitative variables measured then type "None" as your answer. a. Is the average IQ of left handed people higher than the average IQ of right handed people? A unit is _______________ Categorical or Ordinal variable(s) _______________ Quantitative variable(s) _______________ b. For married couples, is there a relationship between owning a pet and whether or not they get divorced? A unit is _______________ Categorical or Ordinal variable(s) _______________ Quantitative variable(s) _______________ c. For college students, is there a relationship between grade point average (GPA) and number of hours spent studying each week? A unit is _______________ Categorical or Ordinal variable(s) _______________ Quantitative variable(s) _______________ d. Individuals in the United States fall into one of a small number of tax brackets based on level of income. Is there a relationship between a person's tax bracket and the percent of income donated to charities? A unit is _______________ Categorical or Ordinal variable(s) _______________ Quantitative variable(s) _______________ PAGE 1 Name: __________________ Class: Date: _____________ 3 The figure for this exercise is a histogram summarizing the responses given by 116 college students to a question asking how much they had slept the previous night. (Data source: sleepstudy dataset on the CD for this book.) a. Describe the shape of the dataset. _________________ b. Are there any outliers? _________________ c. What was the most frequently reported value (approximately) for the amount of sleep the previous night? _________________ d. Roughly, how many students said they slept eight hours the previous night? _________ 4 For each of the following variables, indicate whether the variable is categorical or quantitative: a. Importance of religion to respondent (very, somewhat, or not very important). _________________ b. Hours of sleep last night. _________________ c. Weights of adult women, measured in pounds. _________________ d. Favorite color for an automobile. _________________ PAGE 2 Name: __________________ Class: Date: _____________ 5 In each situation, explain whether it would be more appropriate appropriate to treat the observed data as a sample data from a larger population or as census data . a. An instructor surveys all students in her class to determine whether students would prefer a take exam. _________________ home exam or an in class b. The Gallup organization polls 1000 individuals to estimate the percent of American adults who approve of the President's job performance. _________________ c. A historian summarizes the ages at death for all past Presidents of the United States. _________________ d. A nutritionist wants to determine which of two weightloss programs is more effective. He assigns 25 volunteers to each program, and records the weight loss after two months for each participant. _________________ PAGE 3 ANSWER KEY Name: __________________ 1. 2. Class: 1: *Nominal* Date: _____________ 4. 1: Categorical 2: *Ordinal* 2: Quantitative 3: *Nominal* 4: *Ordinal* 1: *person* 3: Quantitative 4: Categorical *individual* 2: *hand* 3: *IQ* 4: *married couple* 5: *pet*divorce* *divorce*pet* 6: "" *none* 7: *college student* 8: "" *none* 9: *GPA*hours* *hours*GPA* 3. 5. 1: data from the whole population 10: *individual* 2: data from a sample from a larger population *person* 3: data from the whole population 4: data from a sample from a larger population 11: *tax* 12: *percent* 1: approximately symmetric and bell 2: There are no noticeable outliers. 3: 7 hours 4: 14 PAGE 1 shaped