AP Statistics:: Collecting Data

In statistics, the POPULATION refers to:

- **A)** Only the individuals actually measured in a study
- **B)** A numerical summary calculated from sample data
- **C)** The specific treatment applied in an experiment
- **D)** The entire group of individuals that we want information about

A PARAMETER is a numerical summary of:

- **A)** The margin of error
- **B)** Only the sample
- **C)** A single individual
- **D)** The entire population (usually unknown and estimated using sample data)

A STATISTIC is a numerical summary of:

- **A)** A hypothesis test's significance level
- **B)** The entire population directly
- **C)** A sample, used to estimate an unknown population parameter
- **D)** An experimental treatment

A CENSUS is:

- **A)** A random sample of 100 individuals
- **B)** An attempt to collect data from every individual in the entire population
- **C)** Always the best and easiest way to gather data
- **D)** Another name for an experiment

SAMPLING BIAS refers to a systematic tendency for a sampling method to:

- **A)** Perfectly represent the entire population every time
- **B)** Favor certain outcomes or produce samples that are not representative of the population, in a way that is not due to random chance
- **C)** Have no effect on the conclusions drawn from a study
- **D)** Only occur when sample sizes are very large

A CONVENIENCE SAMPLE (choosing individuals who are easiest to reach) typically suffers from what problem?

- **A)** It is a synonym for a simple random sample
- **B)** It always perfectly represents the population
- **C)** It requires the most time and resources of any sampling method
- **D)** It is often biased, since the easiest-to-reach individuals may not represent the broader population

A VOLUNTARY RESPONSE SAMPLE (individuals choose themselves to respond, e.g., online polls) is typically biased because:

- **A)** People with strong opinions (often more extreme in one direction) are more likely to volunteer a response than those with moderate or no opinion, skewing the sample
- **B)** It requires random number generation
- **C)** It is identical to a systematic sample
- **D)** It always produces a perfectly representative sample

A SIMPLE RANDOM SAMPLE (SRS) of size \(n\) is defined as a sample chosen such that:

- **A)** The sample must include exactly half of the population
- **B)** Every individual must volunteer to participate
- **C)** Only individuals from convenient locations are chosen
- **D)** Every possible group of \(n\) individuals from the population has an EQUAL chance of being selected