Question 1

A clinical trial tests a new cholesterol-lowering drug. Out of 2,000 participants, the average reduction in LDL cholesterol is 2 mg/dL with a p-value of $$0.0005. $$Which statement best describes the result?

Accepted Answer

The result is statistically significant, but may lack practical significance if 2 mg/dL is not clinically meaningful.

Question 2

A survey asks respondents to rate their satisfaction with a service as 'Satisfied', 'Neutral', or 'Dissatisfied'. What is the level of measurement for this data?

Accepted Answer

Nominal

Question 3

A researcher randomly selects 10 hospitals and surveys all nurses in those hospitals about job satisfaction. What sampling method is used?

Accepted Answer

Cluster sampling

Question 4

A study records the number of times a patient visits the doctor in a year. What type of data is this?

Accepted Answer

Quantitative discrete

Question 5

A nutrition study collects data on participants' exact daily calorie intake. What is the level of measurement for this variable?

Accepted Answer

Ratio

Question 6

A researcher wants to study the effect of a new teaching method. She randomly assigns students to two groups: one receives the new method, the other receives the standard method. What type of study is this?

Accepted Answer

Experiment

Question 7

A survey asks participants to rank their favorite sports teams from 1 to 5. Why is it incorrect to say that team ranked 1 is 'five times better' than team ranked 5?

Accepted Answer

Because the data is ordinal and differences between ranks are not standardized or meaningful for ratios.

Question 8

A medical researcher collects blood glucose levels (mg/dL) from patients. Which combination of data type and level applies?

Accepted Answer

Quantitative continuous; Ratio

Question 9

A study on exercise habits divides participants into age groups (18–29, 30–49, 50+), then randomly selects 20 from each group. What sampling technique is this?

Accepted Answer

Stratified sampling

Question 10

A researcher measures the temperature in Celsius in several cities. Why is it incorrect to say that $$40^	ext{C} is$$ 'twice as hot' as $$20^	ext{C}$$?

Accepted Answer

Because Celsius is interval data and lacks a true zero, so ratios are invalid.

Question 11

A study collects data on the number of books read by students in a semester. If some students refuse to answer because they read very few books, what type of missing data is this?

Accepted Answer

Missing Not at Random (MNAR)

Question 12

A researcher selects every 10th person from a list of registered voters. What sampling method is this?

Accepted Answer

Systematic sampling

Question 13

A study measures the heights of all students in a school. The average height is calculated for the entire student body. Is this value a parameter or a statistic?

Accepted Answer

Parameter

Question 14

A researcher wants to study the effect of a new diet. She pairs subjects based on age and gender, then randomly assigns one in each pair to the diet and the other to a control group. What experimental design is this?

Accepted Answer

Matched pairs design

Question 15

A study collects data on the number of defective products produced each day in a factory. What type of data is this?

Accepted Answer

Quantitative discrete

Question 16

A survey asks participants to select their favorite color. The researcher assigns numbers to each color (1 = Red, 2 = Blue, 3 = Green) and calculates the mean. Why is this calculation meaningless?

Accepted Answer

Because color is nominal data and the numbers are arbitrary labels, not quantities.

Question 17

A study measures the time (in seconds) it takes for runners to complete a race. What is the level of measurement for this variable?

Accepted Answer

Ratio

Question 18

A researcher collects data on the years in which major earthquakes occurred. What is the level of measurement for the variable 'year'?

Accepted Answer

Interval

Question 19

A study divides a population into regions, randomly selects some regions, and surveys all residents in those regions. What sampling method is this?

Accepted Answer

Cluster sampling

Question 20

A pharmaceutical company conducts its own study on a new drug and reports positive results. What is the main concern with this data source?

Accepted Answer

Potential conflict of interest and bias due to the company's financial stake in the outcome.

Introductory Statistics Chapter 1 Practice Exam – Step-by-Step Study Guidance

Guida di studio - Domande di pratica

Study guide - Flashcard