Question 1

Which of the following best describes the main purpose of statistics as defined in the study materials?

Accepted Answer

To collect, organize, summarize, and analyze information to draw conclusions or answer questions, and provide a measure of confidence in those conclusions.

Question 2

A researcher wants to know if a new medication reduces blood pressure more effectively than the current standard. She randomly assigns patients to two groups, gives one group the new medication and the other the standard, and measures their blood pressure after 8 weeks. What type of study is this?

Accepted Answer

Designed experiment

Question 3

Which of the following is a quantitative variable?

Accepted Answer

Number of students in a classroom

Question 4

Suppose you want to estimate the average income of households in a city. You divide the city into neighborhoods and randomly select 5 neighborhoods. Then you survey every household in those neighborhoods. What sampling method are you using?

Accepted Answer

Cluster sampling

Question 5

Which of the following is an example of a discrete variable?

Accepted Answer

The number of cars sold by a dealership in a day

Question 6

A survey asks, 'Do you support the current mayor’s plan to improve the city’s parks?' and 'Do you support the mayor’s plan to increase taxes for park improvements?' Which type of bias could be introduced by the order of these questions?

Accepted Answer

Response bias

Question 7

Which of the following best describes a confounding variable?

Accepted Answer

A variable whose effect cannot be distinguished from another explanatory variable in the study.

Question 8

A sample is obtained by selecting every 10th person from a list of all employees at a company. What type of sampling is this?

Accepted Answer

Systematic sampling

Question 9

Which of the following is a source of nonsampling error?

Accepted Answer

A respondent misinterpreting a survey question

Question 10

A researcher wants to study the effect of exercise on stress levels. She recruits volunteers and lets them choose whether to join the exercise group or the control group. What is the main problem with this study design?

Accepted Answer

It introduces selection bias because the groups are self-selected.

Question 11

Which of the following best describes a stratified sample?

Accepted Answer

Dividing the population into homogeneous groups and randomly sampling from each group

Question 12

Which of the following statements is true regarding correlation and causation?

Accepted Answer

Correlation does not imply causation.

Question 13

A researcher collects data on the number of hours students study and their exam scores. She finds a strong positive correlation. Which of the following is a lurking variable that could affect this relationship?

Accepted Answer

The difficulty of the exam

Question 14

Which of the following is an example of a parameter?

Accepted Answer

The average height of all students in a university

Question 15

In a double-blind experiment, who knows which treatment the experimental unit is receiving?

Accepted Answer

Neither the experimental unit nor the researcher

Question 16

Which formula would you use to calculate the sample mean $$\bar{x}$$ for a set of $$n$$ observations $$x_1$$, $$x_2$$, ..., x_n$$?

Accepted Answer

$$\bar{x} = \frac{\sum_{i=1}^{n} x_i}{n}$$

Question 17

A researcher wants to compare the effectiveness of two diets. She matches participants by age and gender, then randomly assigns one from each pair to each diet. What experimental design is this?

Accepted Answer

Matched-pairs design

Question 18

Which of the following is an example of response bias?

Accepted Answer

Respondents giving answers they think are socially acceptable rather than their true opinions

Question 19

Which of the following best describes a placebo in an experiment?

Accepted Answer

A false treatment disguised as the real treatment

Chapter 1: Data Collection – Applied Statistics Study Notes

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