Unit 1 Challenge 1 1. A survey on Internet usage was conducted among a group of 200 students in the school cafeteria. It was found that 100 students spend at least two hours online every day. Which of these is an example of descriptive statistics? A: 50% of the students surveyed spend at least two hours online each day. 2. If numbers collected from a survey are measurements, what are these measurements called before you perform any calculations? A: raw data 3. Select the two categories that would yield quantitative data. A: Age of pet, Weight of pet 4. Which of these data sets represent discrete data? A: Number of questions answered incorrectly in a multiple-choice quiz Challenge 2 1. A production company is interested in collecting information on the impact of an educational documentary on everyone that watched it at the film festival. Which statement is true? A: The group of people that watched the documentary at the festival represents the population. 2. Which of these random samples qualifies as a representative sample if studying the opinion of people who use online shopping websites? A: Consumers who order products online 3. Which of these is an example of systematic random sample? A: Picking out the telephone number of every 20th person from a directory. 4. Which of these statements best defines a stratified random sample? A: It is a sample where the population is first broken into homogenous groups and then elements are randomly selected, in proportion, from each group. 5. Which of these is an example of multi-stage sampling? A: Choosing New York as a sample, then selecting a sample of zip codes within New York, then sampling the names of people living in those zip codes. Challenge 3 1. Select the statement that expresses an approach used with observational studies. A: "We took all those notes. We recorded customer counts, menus, food prices, even the general atmosphere of the food truck environment." 2. Which of these situations best describes a retrospective observational study? A: A doctor analyzing the medical history of a person. 3. Analyzing the results of rolling a fair die 100 times refers to which of these principles? A: Replication 4. Which of these statements is true regarding a randomized block design experiment? A: Random allocation of treatment and control groups is done within the divided groups. 5. Select the TRUE statement for completely random design. A: The experimental units are assigned randomly to exactly one control group and one or more treatment groups. 6. Which of these statements best describes a matched-pair design? A: A design in which only two treatments are tested on pairs of similar subjects. 7. Which of the following is NOT an example of a survey? A: A nutritionist is studying the relationship between eating carbohydrates and gaining weight. The nutritionist recorded the diets and weights of 10 people for a year. 8. Which of these represents a blind experiment? A: Asking a group of adults to compare the taste of coffee without revealing the names of the brands. 9. By accident, Janae has been making decaffeinated coffee for her co-workers for the entire week. But some of her co-workers have claimed that the extra boost of caffeine has helped them focus on their work. What does the placebo effect mean in this specific situation? A: The benefit is due to the fact that the co-workers are given a "treatment" (coffee, although decaffeinated) and not an effect of the "active ingredient" (caffeine). Challenge 4 1. When Ben increases the temperature difference between two junctions, the voltage also increases. What type of variable is voltage in the above situation? A: Response 2. Which of these represents a binomial question? A: Do you own a rabbit? 3. Kendra reads in Modern Dog Magazine that the average age of dogs currently alive is 4.8 years. To determine if this finding applies to the customers in her pet store, Kendra surveys every fifth customer in her store who owns a dog and asks the age of their dog. She collects data for seven weeks and obtains the following averages. Select the statement that is true about Kendra's sample. A: Kendra's samples are precise but not accurate. Week Average Age (in years) 1 3.7 2 3.8 3 4.2 4 4.1 5 3.9 6 3.9 7 4.0 4. In 2000, there were 4,578 residents living in multi-family housing units. In 2010, there were 4,312 residents living in multi-family housing units. Select the true statement about residents living in multi-family housing units from 2000 to 2010. Percentages are rounded to the nearest tenths place. A: The absolute change is -266 residents and the relative change indicates a decrease of 5.8%. 5. A company’s market share went from 50 to 65 percent of the total market. Of the following choices, which two statements about the company's market shares are true? A: There was a 30% increase in market shares., Market shares rose by 15 percentage points. 6. The following are the Consumer Price Index (CPI) for the years 1990-1992. All of the values use a reference year of 1985. A: $100 in 1985 would be equivalent to $145 in 1992. Challenge 5 1. How about members of a local professional sports team who are conducting a survey? Which data collection method would provide biased results for the question "What is your favorite sport?" A: Ask people attending a soccer game. 2. Kendra decides to go door-to-door and survey people who live near the pet shop she owns. On Tuesday, Kendra steps out during her lunch break and finds that many people aren't home. Of the people who are home, Kendra discovers that most of them are elderly or stay-at-home parents. Discovering that many people are not available to participate in her survey is an example of bias. A: nonresponse 3. Tim mailed a lot of his surveys to married couples. However, he included only the name of the male spouse in the mailing address. As a result, Tim has systematically excluded the opinions of female spouses from his survey. Ideally, Tim would prefer to have a 50/50 split in male and female respondents in his sample. Based upon the above scenario, which of the following is TRUE? A: Tim has uncovered selection bias in his methods. 4. Select the example that represents self-selected sampling. A: Naomi posts a request for survey volunteers on the restaurant's Facebook page. 5. Which statement about systematic errors is TRUE? A: They can occur when a selection bias is present. 6. After all of the surveys have been compiled and analyzed, the calculated level of satisfaction for “overall quality” for a sample was 6.2 ± 0.5. Select the true statement regarding the margin of error of this scenario