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Identify the population, sample, and the sample data set.
A poll of households in a city found that planned to install solar panels within the next year.
A psychologist observes the study habits and test scores of high school students to see if those who study more hours tend to achieve higher scores. The students are not given any instructions about how much to study. Is this an observational study or an experiment? Justify your answer.
A research team is evaluating a new dietary supplement intended to enhance memory. They select college students aged to , all from the same university. The students are randomly divided into two groups: one receives the supplement, and the other receives a placebo. Both groups take their assigned pills daily for six weeks, and memory tests are administered before and after the treatment. What is a potential flaw in this experimental design, and how could it be addressed?
Determine whether the following data set is a population or a sample. Explain your reasoning.
The annual revenue of each store in a national retail chain.
Is the following survey question biased? If so, provide a neutral alternative. Do you agree that the mayor's proposal to limit public park hours is a bad idea that will inconvenience families?
Which of the following is the best reason to run a presurvey (pilot test) before administering a closed-question questionnaire to a large sample?
A survey question asks: How many times do you participate in group study sessions each week?
Is this question biased? If so, choose the best revision from the options below.
Determine whether the data set consisting of the number of books checked out by all library visitors during a month is a population or a sample. Explain your reasoning.
A national research group now recruits survey participants through a smartphone app and by sending SMS invitations instead of using landline calls. Explain how these recruitment methods can introduce nonsampling error, and identify the main types of nonsampling error likely to arise.
You design an online survey about commuter students' use of campus transportation. You e-mail the survey to a convenience sample of students and receive completed surveys. Which of the following is the correct response rate and the most likely nonsampling error affecting representativeness?