Question 1

A researcher collects the number of births and birth rates per 1,000 population in the U.S. for each year from 1990 to 1994. What type of study is this?

Accepted Answer

Descriptive, because it summarizes data from a specific group without generalizing.

Question 2

A researcher uses a random sample of 1,000 people to estimate the percentage of people lacking health insurance in a U.S. city. What type of study is this?

Accepted Answer

Inferential, because it uses sample data to make conclusions about a population.

Question 3

A computer network manager wants to test the reliability of new Ethernet cables. She randomly selects one box out of five, then randomly selects 10 cables from that box. What is the sample in this scenario?

Accepted Answer

The 10 cables selected from the chosen box.

Question 4

In a contest with six finalists (Lisa, Melina, Ben, Danny, Eric, and Joan), how many possible samples of size 3 can be drawn without replacement?

Accepted Answer

$$C(6,3) = 20$$

Question 5

If a simple random sampling method is used to select a sample of 3 from the 6 finalists, what is the probability that Ben, Danny, and Joan are all selected?

Accepted Answer

$$\frac{1}{20}$$

Question 6

A magazine is awarding a cash prize to 10 winners from 400 contestants. If a list of random numbers between 1 and 400 is used to select the winners, what type of sampling is this?

Accepted Answer

Simple random sampling

Question 7

A researcher selects 38 schools from a district and interviews all teachers at those schools. What type of sampling is used?

Accepted Answer

Cluster sampling

Question 8

An education researcher randomly selects 12 freshmen, 10 sophomores, 9 juniors, and 6 seniors from a college. What type of sampling is this?

Accepted Answer

Stratified sampling

Question 9

A personnel manager randomly selects 20 software engineers and 20 hardware engineers from a company to survey about career opportunities. Does this sampling plan result in a random sample?

Accepted Answer

No, because it is stratified by job type, not purely random.

Question 10

Which of the following best describes a simple random sample?

Accepted Answer

Every individual has an equal chance of being selected.

Question 11

A researcher wants to estimate the average commute time for employees in a large company. She divides employees into departments and randomly selects some departments, then surveys all employees in those departments. What sampling method is used?

Accepted Answer

Cluster sampling

Question 12

A hospital administrator wants to study patient satisfaction. She randomly selects 10 patients from each age group (18-29, 30-49, 50-64, 65+). What type of sampling is this?

Accepted Answer

Stratified sampling

Question 13

A researcher wants to estimate the average number of hours students study per week. She selects every 10th student from an alphabetical list. What sampling method is this?

Accepted Answer

Systematic sampling

Question 14

Which of the following is an example of inferential statistics?

Accepted Answer

Using a sample to estimate the average height of all adults in a city.

Question 15

A researcher wants to know the average cholesterol level of adults in a city. She measures the cholesterol of 200 randomly selected adults. What is the population in this study?

Accepted Answer

All adults in the city.

Question 16

A study reports that 19.1% of people aged 25-39 lack health insurance, based on a random sample. What is the parameter in this context?

Accepted Answer

The true percentage of all people aged 25-39 lacking health insurance.

Question 17

Which of the following is NOT a characteristic of a simple random sample?

Accepted Answer

The sample is divided into groups and one group is selected.

Question 18

A researcher wants to study the effect of a new drug. She randomly assigns patients to receive either the drug or a placebo and compares outcomes. What type of study is this?

Accepted Answer

Experimental study

Question 19

A school administrator wants to estimate the average GPA of students. She randomly selects 5 classes and records the GPA of every student in those classes. What sampling method is used?

Accepted Answer

Cluster sampling

Question 20

A researcher wants to estimate the average income of households in a city. She divides the city into neighborhoods and randomly selects households from each neighborhood. What sampling method is this?

Accepted Answer

Stratified sampling

Fundamental Concepts in Statistics: Sampling, Study Types, and Data Classification

Guida di studio - Domande di pratica

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