Question 1

Which of the following best describes the difference between a population and a sample in statistics?

Accepted Answer

A population is the entire group you want information about, while a sample is a smaller group taken from the population.

Question 2

A researcher wants to know the average height of all university students. She measures the height of 200 randomly selected students. In this context, what is the parameter and what is the statistic?

Accepted Answer

The parameter is the average height of all university students; the statistic is the average height of the 200 students.

Question 3

Which of the following is an example of categorical (qualitative) data?

Accepted Answer

The eye color of students in a classroom.

Question 4

A survey asks respondents to rate their satisfaction on a scale from 1 (very dissatisfied) to 5 (very satisfied). What is the level of measurement for this data?

Accepted Answer

Ordinal

Question 5

Which of the following best illustrates the concept of confounding in an observational study?

Accepted Answer

Failing to identify the true cause of an observed effect due to the influence of an outside variable.

Question 6

A researcher deletes all cases with missing values from her dataset. What is a potential drawback of this approach?

Accepted Answer

It can introduce bias if the missing data are not missing completely at random.

Question 7

Which of the following is a key feature of a double-blind experiment?

Accepted Answer

Neither the subjects nor the researchers know who receives the treatment or placebo.

Question 8

Suppose a study finds that ice cream sales and drowning incidents both increase during the summer. What is the most likely explanation for this observation?

Accepted Answer

A confounding variable, such as temperature, affects both ice cream sales and drowning incidents.

Question 9

Which of the following sampling methods is most likely to produce a biased sample?

Accepted Answer

Voluntary response sampling

Question 10

A researcher collects data on the number of siblings each student has. What type of data is this?

Accepted Answer

Discrete quantitative data

Question 11

Which of the following is an example of data measured at the ratio level?

Accepted Answer

Height in centimeters

Question 12

A study uses a systematic sampling method. Which of the following best describes this method?

Accepted Answer

Subjects are chosen at regular intervals from an ordered list.

Question 13

Which of the following statements about statistical significance is correct?

Accepted Answer

A result is statistically significant if it is unlikely to occur by chance, usually with probability $$\u003c 5\%.$$

Question 14

Which of the following is a common pitfall in statistical studies?

Accepted Answer

Reporting self-selected survey responses as representative of the population

Question 15

A researcher wants to compare the effects of two medications. She randomly assigns subjects to two groups, gives one group medication A and the other medication B, and measures their outcomes. What type of study is this?

Accepted Answer

Experiment

Question 16

Which of the following best describes missing data that is 'missing completely at random'?

Accepted Answer

Every value has an equal chance of being missing, unrelated to any variable.

Question 17

Which of the following is NOT a level of measurement?

Accepted Answer

Relative

Question 18

A study collects data on the favorite color of 500 children. What is the best level of measurement for this data?

Accepted Answer

Nominal

Question 19

Which of the following best describes a cross-sectional observational study?

Accepted Answer

Data is collected at one point in time.

Question 20

Which of the following is a benefit of randomization in experimental design?

Accepted Answer

It helps balance unknown factors between treatment groups, reducing bias.

Chapter 1: Introduction to Statistics – Key Concepts and Methods

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