Problem-Solving and Data Analysis
Decide what a study can conclude. Random sampling lets results apply to a larger population. Random assignment to groups lets a study show cause and effect.
Choices that claim too much are usually wrong. Without random assignment, a study can show an association but not a cause.
Full skill name: Evaluating statistical claims: observational studies and experiments
Pick an answer to check it and see why. Practice sets also have grid-ins, where you type the answer.
Easy
A study of the students at an elementary school with grades 1 through 5 found that the students who know more vocabulary words tend to be able to jump farther in a standing long jump. Which of the following is the most likely explanation for this association?
Medium
Researchers randomly assigned 300 volunteers to either take a new supplement or a placebo, then measured their sleep quality. The supplement group slept better on average. Which of the following conclusions is best supported by the study?
Hard
A company that makes a fitness app invited all of its users to complete an online survey, and 2,000 users chose to respond. The users who reported using the app's meditation feature at least 3 times per week reported lower stress levels, on average, than the users who reported using the feature less often. Which of the following is the most appropriate conclusion?
Start a set in this skill. Every answer comes with an explanation.
31 questions in the bank: 4 Easy, 13 Medium, 14 Hard.