options: Use probability to evaluate outcomes of decisions.

Summarize, represent, and interpret data on a single count or measurement variable.

Understand and evaluate random processes underlying statistical experiments.

Summarize and describe distributions.

Calculate expected values and use them to solve problems.

Use the rules of probability to compute probabilities of compound events in a uniform probability model.

Make inferences and justify conclusions from sample surveys, experiments, and observational studies.

Draw informal comparative inferences about two populations.

Use random sampling to draw inferences about a population.

Interpret linear models.

Develop understanding of statistical variability.

Understand independence and conditional probability and use them to interpret data.

Summarize, represent, and interpret data on two categorical and quantitative variables.

Investigate patterns of association in bivariate data.

Investigate chance processes and develop, use, and evaluate probability models.
problem_activity: Task
A student interested in comparing the effect of different types of music on short-term memory conducted the following study:  80 volunteers were randomly assigned to one of two groups.  The first group was given five minutes to memorize a list of words while listening to rap music.  The second group was given the same task while listening to classical music.  The number of words correctly recalled by each individual was then measured, and the results for the two groups were compared.
Is this an experiment or an observational study?  Justify your answer.
In the context of this study, explain why it is important that the subjects were randomly assigned to the two experimental groups (rap music and classical music).


correct_option_index: 6