Practice 1 Solutions
Identify the population and sample from the scenario.
- Two hundred residents of Baytown were surveyed about the proposal for a new park.
Population: All residents from Baytown
Sample: Two hundred residents from Baytown
- Lights Unlimited tests fifty lightbulbs from a batch of 10,000 bulbs.
Population: Batch of 10,000 lightbulbs
Sample: 50 lightbulbs from the batch
Determine if the question will result in descriptive or inferential statistics. Then name the population.
- What is the most common eye color among all students at Adams Elementary School?
Type: descriptive
Population: all students at Adams Elementary
- How did the teachers at Whittier Middle School describe the relationship between the new math curriculum and student learning?
Type: inferential
Population: teachers at Whittier Middle School
- Which fish species has the largest population in the lake, based on the sample taken?
Type: inferential
Population: fish in the lake
- What are the age ranges of participants in The Novel Ideas book club?
Type: descriptive
Populations: book club participants
Explain the study and type of variable.
- A researcher wants to know when people start wearing jackets this fall, so they record the number of people wearing jackets in a park in September.
Sample: This is an observational study with qualitative variables. The researcher is not changing behaviors or interacting with the people at the park. They are only counting the people wearing jackets.
- To prepare for a test, a researcher separated students into two groups. The control group used the standard text-based study guide. The treatment group used a visual study guide. The test scores were compared to determine the effectiveness of each study guide.
Sample: This is an experimental study with a quantitative variable. The researcher is comparing the test scores of two groups: one using a visual study guide and the other using a text-based study guide.
Name the type of study conducted, the population, and name and classify the variables as quantitative (Q) or categorical (C).
- To compare their town’s rainfall to the state average, Alcott Elementary students measured rainfall over a one month period.
Type of Survey: observational
Population: rainfall in the state
Variable: rainfall (Q)
- A botanist classified a sample of trees by species in Dale City Park.
Type of study: observational
Population: trees in Dale City Park
Variable: species (C)
- A customer satisfaction survey was sent to all customers of Neal’s Knick-Knacks to rate their experience as “good,” “fair,” or “poor.”
Type of study: sample survey
Population: customers of Neal’s Knick-Knacks
Variable: experience (C)
- To determine if any machines produce a higher number of product defects than others in Fran’s Factory, quality control wants to analyze the hourly defect rates of each machine.
Type of study: observational
Population: machines in Fran’s Factory
Variables: machine (C), number of defects (Q)