1. A company tests a new feature on its app by rolling it out to all users in one city. Which sampling method is being used?
2. A health department randomly selects hospitals from different regions and surveys all doctors in those hospitals about patient care. Which sampling method is being used?
3. A university wants to know how many students prefer online learning. They send a survey link to all students via email. What could be a potential source of bias?
4. A researcher wants to estimate average sleep time for students at a large high school. She divides students by grade level and then randomly selects 40 students from each grade to keep a sleep diary for a week. Some students might forget to record sleep. Which sampling method is being used?
5. To understand exercise habits, researchers survey people at a gym. Which characteristic makes this sample biased?
6. To understand the impact of air pollution, researchers monitor air quality in various neighborhoods and correlate it with health records. Is this an experiment or an observational study?
7. A health department wants to know whether people who bike to work report lower stress. They survey commuters about how they travel and their stress level, without asking anyone to change their commute habits. Some people may misreport their stress. Is this an experiment or an observational study?
8. A researcher wants to learn whether a new 5-minute stretching routine reduces muscle soreness after running. She randomly assigns 60 runners to either do the stretching routine after each run or to keep their usual cool-down routine, then compares reported soreness after two weeks. Is this an experiment or an observational study?
9. A researcher is interested in the study habits of high school students. They select a random sample of schools and survey all students in those schools. Which sampling method is being used?
10. A researcher wants opinions about cafeteria food at a large university. She divides students into groups by year (first-year, sophomore, junior, senior) and randomly selects 50 students from each year to survey. This helps ensure each year is represented. Which sampling method is being used?
11. To choose a new school mascot, a student council surveys 300 students by standing at the entrance to the gym during a varsity basketball game. Students who don’t attend games are underrepresented. Which sampling method is being used?
12. A student wants to estimate the average price of a textbook at her college bookstore. She records the prices of the first 30 textbooks she sees on the “New Arrivals” shelf. That shelf mostly contains expensive new editions. Which characteristic makes this sample biased?
13. A sports scientist tests a new hydration drink. She randomly assigns athletes to drink either the new drink or plain water during practice, then measures their sprint times afterward. Athletes know what they drank, which could affect effort. To reduce bias, the researchers should:
14. A grocery store wants to know which of two shelf layouts leads to higher sales. For one month, Store 1 uses Layout A and Store 2 uses Layout B, then sales are compared. The stores are in different neighborhoods with different customer bases. Which characteristic makes this comparison potentially biased?
15. To assess the impact of a new teaching method, teachers use it in some classes while others continue with the old method. Students' test scores are compared. Is this an experiment or an observational study?
16. A university wants to compare average dining hall satisfaction between students living on campus and off campus. They take a list of all students and randomly select 200 on-campus students and 200 off-campus students to survey. This ensures both living situations are included. Which sampling method is being used?
17. A company wants to compare two training videos for new employees. New hires are randomly assigned to watch Video A or Video B, and then all take the same skills test. The company controls which video each person watches. Is this an experiment or an observational study?
18. A teacher wants to estimate the average number of hours students at her school spend on homework each week. She divides the school into grade levels (9th, 10th, 11th, 12th) and randomly selects 30 students from each grade to survey. Which sampling method is being used?
19. A doctor wants to study whether people who drink coffee daily have different average blood pressure than people who do not. She reviews existing medical records and compares blood pressure for patients who already report drinking coffee daily versus those who do not. Is this an experiment or an observational study?
20. A news website wants to estimate what percent of all adults in a state approve of the governor. To reduce bias, what is the best method to collect data for this purpose?
21. A city council wants to estimate support for a new bus route. A volunteer stands outside the downtown transit station from 5–6 PM on weekdays and asks the first 200 riders who pass by to answer a short poll. Many residents who don’t use transit at that time are not included. Which sampling method is being used?
22. A school principal wants to know what percentage of students at the school eat breakfast. She stands at the cafeteria entrance one morning and asks the first 120 students who walk in whether they ate breakfast. Which characteristic makes this sample biased?
23. A survey is conducted to understand the commuting habits of city residents. Surveys are distributed to every household in a randomly chosen neighborhood. Which sampling method is being used?
24. A university wants to estimate the average amount of sleep per night among all its students. A researcher surveys only students in an 8 a.m. class because they are easy to reach, and then reports the result as the university-wide average. To reduce bias, the researchers should:
25. To determine the effectiveness of a new advertising campaign, a company surveys every 10th customer who makes a purchase online. Which sampling method is being used?
26. A health study tracks the eating habits of a group of volunteers over five years, observing their natural behaviors without intervention. Is this an experiment or an observational study?
27. A nutritionist wants to study the eating habits of teenagers. They observe what teenagers purchase at a school cafeteria without any interaction. Is this an experiment or an observational study?
28. A high school club surveyed its 50 members about their participation in two fundraisers: a car wash and a bake sale. The results are shown in the Venn diagram below. How many members participated in the bake sale but not the car wash?
29. To evaluate the popularity of a new app, a company surveys users who have downloaded it within the last week. Which characteristic makes this sample potentially biased?
30. To gather feedback on a new product, a company places an online survey link on its website. Which sampling method is most likely being used?
31. To test a new teaching technique, teachers use it in some classes while others continue with traditional methods. Which study design would avoid bias?
32. To understand commuting patterns, a city surveys every fifth person who uses public transportation. Which sampling method is being used?
33. To evaluate customer satisfaction, a restaurant gives a feedback form only to customers who order dessert. Which characteristic makes this sample biased?
34. A company tests a new product by giving it to a selected group of loyal customers and asking for feedback. Which sampling method is being used?
35. Researchers want to examine how a new drug affects blood pressure. Participants are randomly assigned to receive either the drug or a placebo. Is this an experiment or an observational study?
36. To assess the popularity of a new TV show, a broadcaster surveys viewers who watched the premiere episode. Which characteristic makes this sample biased?
37. A city council wants to gauge the public’s reaction to a new policy. They conduct a phone survey using a random digit dial method. Which sampling method is being used?
38. To determine the effectiveness of a new advertising campaign, a company compares sales data before and after the campaign launch. Which study design would avoid bias?
39. A tech company wants to test a new application feature. They select a diverse group of users based on age and location. Which sampling method is being used?
40. To evaluate a training program, a company assigns some employees to the program while others continue usual work. Their performance is monitored. Is this an experiment or an observational study?
41. To investigate the link between diet and health, researchers survey people about their eating habits and health status. Is this an experiment or an observational study?
42. A school wants to understand the eating habits of its students. They select every 10th student entering the cafeteria to participate in a survey. Which sampling method is being used?
43. To evaluate a new diet program, participants are required to follow it strictly. Researchers monitor weight loss over three months. Is this an experiment or an observational study?
44. A researcher is studying the effect of sleep on memory. Participants are asked to follow their regular sleep patterns and complete memory tests. Is this an experiment or an observational study?
45. A city plans to survey residents about a new park. They randomly select households from each neighborhood to ensure all areas are represented. Which sampling method is being used?
46. To evaluate a new marketing strategy, a company compares sales data from regions where the strategy was implemented to those where it wasn't. Which study design would avoid bias?
47. A company wants to understand employee satisfaction. They send a survey to a random sample of 100 employees. Which sampling method is being used?
48. To explore customer satisfaction, a store selects a sample of customers who have left feedback in the past month. Which characteristic makes this sample potentially biased?
49. A health clinic wants to determine the average waiting time for patients. They record the waiting time for every patient visiting the clinic over a week. Which study design is being used?
50. A market researcher wants to understand consumer preferences. They randomly call 200 phone numbers from a database. Which sampling method is being used?
51. To test a new training program, a company randomly assigns employees to either follow the new program or continue their usual tasks. Is this an experiment or an observational study?
52. To study screen time, a teacher randomly selects 4 classrooms from the entire school and surveys every student in those selected classrooms. Students in other classrooms have no chance to be surveyed. Which sampling method is being used?
53. A streaming service wants to estimate customer satisfaction. They email a survey only to subscribers who contacted customer support in the last month. These subscribers may be unusually unhappy or unusually engaged. To reduce bias, the researchers should:
54. A researcher wants to study the effect of a new diet on weight loss. They randomly assign 100 participants to either follow the new diet or continue their normal eating habits. Is this an experiment or an observational study?
55. A researcher wants to study the effects of sleep on cognitive function. They observe participants' sleep patterns and test their cognitive function without altering their sleep habits. Is this an experiment or an observational study?
56. A city council wants to gauge public opinion on a new park development. They send out surveys to all residents living within a 1-mile radius of the proposed site. Which characteristic makes this sample potentially biased?
57. A gym wants to assess member satisfaction with new equipment. They ask every fifth person who enters the facility. Which sampling method is being used?
58. A high school wants to know students' opinions about the new lunch menu. They survey every 10th student entering the cafeteria. Which sampling method is being used?
59. To assess the effectiveness of a new teaching method, a school randomly selects 50 students from each grade level to participate. Which sampling method is being used?
60. A pharmaceutical company conducts a trial to test a new drug. They give the drug to one group of patients and a placebo to another. Which study design is being used?
61. A teacher wants to see if a new curriculum improves student performance. They implement the curriculum in one class and compare it to another class with the old curriculum. Which study design is being used?
62. A nonprofit wants to estimate how many residents support building a new community center. They plan to knock on doors in one neighborhood because it is close to their office. To get a more representative result for the whole city, what is the best method to collect data?
63. A school nurse wants to know how many students regularly eat breakfast. She gets a list of all students and selects every 15th student on the list to complete a survey. If the list is ordered by homeroom, some grades may be overrepresented. Which sampling method is being used?
64. A wildlife group wants to estimate the average number of birds seen per hour in a park. Volunteers choose when to go birdwatching and then report their counts online. Most volunteers go on sunny weekend mornings. Which characteristic makes this sample biased?
65. A town wants feedback on a proposed park renovation. They post a QR code at the current park entrance asking visitors to complete a survey. People who never visit the park are not included. Which sampling method is being used?
66. To study the health effects of smoking, researchers follow smokers and non-smokers for 10 years. Is this an experiment or an observational study?
67. A supermarket wants to know customer satisfaction. They ask shoppers leaving the store for feedback. Which sampling method is being used?
68. A scientist wants to study the natural behaviors of birds in a forest. They observe the birds from a distance without interfering. Is this an experiment or an observational study?
69. A university wants to evaluate student satisfaction with online classes. They send a survey to the first 100 students who log into the online portal. Which sampling method is being used?
70. A doctor wants to see whether a new reminder app increases medication adherence. Patients in her clinic are randomly assigned to either use the app or not use it, and adherence is checked after 8 weeks. Some patients stop using the app early. Is this an experiment or an observational study?
71. A teacher wants to test whether listening to instrumental music improves quiz scores. She randomly assigns half the class to take a quiz with instrumental music playing and the other half to take the same quiz in silence. Students are tested at the same time of day. Which study design would avoid bias from students choosing their condition?
72. A county wants to estimate the percentage of households with reliable internet. They have a complete address list and use a random number generator to select 600 addresses to mail a survey. Some households may not respond, creating nonresponse bias. Which sampling method is being used?
73. To evaluate the effect of a new software tool, a company randomly assigns some employees to use it while others continue with the old system. Is this an experiment or an observational study?
74. To determine the average height of students in a large university, the researchers randomly select 50 students from each year (freshman, sophomore, junior, senior). Which sampling method is being used?
75. A principal wants to estimate the average time students spend on homework each night. She sends an optional online survey link through the school newsletter, and only students who choose to respond are counted. Students with strong feelings may be more likely to answer. Which characteristic makes this sample biased?