A district lists all 2,400 juniors, assigns each a number, and uses a random-number generator to choose 120 numbers. What sampling method is this?

A researcher separates voters into age groups 18-29, 30-49, 50-64, and 65+, then randomly selects people from each group in proportion to the voter population. What sampling method is this?

A school randomly selects 6 entire English classes from the 40 English classes offered and surveys every student in those selected classes. What sampling method is this?

A library chooses a random starting point on its alphabetical member list, then surveys every 30th member after that. What sampling method is this?

A student asks the first 40 classmates who enter the cafeteria whether the school should add a later bus. What sampling method is this?

A conference app asks any attendee who wants to rate the keynote speaker to open a survey link. What sampling method is this?

A hospital groups nurses by shift, then randomly selects 20 nurses from each shift to answer a staffing survey. What sampling method is this?

A city randomly selects 12 apartment buildings and surveys every household in those buildings about recycling service. What sampling method is this?

A factory quality team randomly chooses the 12th battery from a production line, then tests every 25th battery after it. What sampling method is this?

A pollster has a complete list of city households and uses software to randomly select 600 households, with each household equally likely. What sampling method is this?

A store manager surveys customers standing near the checkout lane at 5 p.m. because they are available. What sampling method is this?

A college sorts students by major, then randomly chooses students from each major so the sample matches the college's major percentages. What sampling method is this?

A polling company randomly selects 25 city blocks, then interviews every adult living on those blocks. What sampling method is this?

A company assigns every employee an ID number and uses a lottery program to choose 75 IDs for a benefits survey. What sampling method is this?

A radio host asks listeners to call in about a new stadium tax and reports the results from the callers. What bias is introduced?

A school surveys only students in AP Statistics about whether all students want a later start time. What bias is introduced?

A county mails surveys to 5,000 randomly chosen residents, but only 300 return them. What bias is most likely?

A teacher asks students to raise a hand if they broke the homework policy while classmates watch. What bias is most likely?

A city estimates adult exercise habits by interviewing people leaving one fitness center. What bias is introduced?

A restaurant leaves comment cards on tables and analyzes only the cards customers choose to submit. What bias is introduced?

An exit poll samples every tenth voter but skips a precinct in an apartment complex because it is hard to reach. What bias is introduced?

A company surveys the first 50 employees entering the main lobby about remote work. What bias is most likely?

A school posts an online poll about athletics and allows anyone with the link to vote. What bias is introduced?

A survey asks, "How much do you support the excellent new attendance policy?" What bias is most likely?

A pollster randomly samples 800 registered voters from a city voter list. Can the result be generalized to the city's registered voters?

A principal surveys students in one lunch period and reports the result as the opinion of all students at the school. Can this be generalized?

A city randomly chooses 20 neighborhoods and surveys every household in those neighborhoods about trash pickup. Can results be generalized to city households?

A district posts a parent survey link on social media, then uses the responses to describe all district parents. Can the result be generalized?

A high school randomly samples students from each grade in the same proportions as the school enrollment. Can results be generalized to the school's students?

A health study surveys patients leaving one hospital and reports conclusions about exercise habits of all adults in the county. Can this be generalized?

An online store randomly samples 1,000 customer accounts from its complete account database. Can the results be generalized to that store's customers?

A coach surveys students in only his classes and reports the results as the opinion of all athletes at the school. Can this be generalized?

A school survey used only seniors, but the goal is to estimate opinions of the whole high school. What method best fixes the flaw?

A city survey used only an online form, missing households without internet access. What method best fixes the flaw?

A club poll counted only members who chose to reply to a group chat. What method best fixes the flaw?

A city wants each neighborhood represented in proportion to its population, but a first survey overrepresented downtown. What method best fixes the flaw?

A transit survey interviewed riders only at the downtown stop, missing other routes and times. What method best fixes the flaw?

A mail survey had many nonresponses from selected households. What method best fixes the flaw?

A student samples every 4th name from a list that repeats clubs in the same order, so one club is overselected. What method best fixes the flaw?

A teacher surveyed only one elective class to estimate opinions of all students. What method best fixes the flaw?