Q: If a study reports that 'the average salary increased by 10%,' what is the correct formula to calculate the new average salary if the original average was $50,000?

$$50,000 + (50,000 \times 0.10)$$

Q: A study finds a difference in test scores between two groups. Which of the following is the correct formula for the percentage difference if Group A scored 80 and Group B scored 100?

$$\frac{100 - 80}{100} \times 100\%$$

Question 1

Which of the following best describes the main purpose of statistics in scientific research?

Accepted Answer

To summarize, analyze, and interpret data to draw meaningful conclusions.

Question 2

A pharmaceutical company wants to test a new drug. They randomly assign patients to receive either the drug or a placebo, without telling them which they receive. What is this an example of?

Accepted Answer

Double-blind experiment

Question 3

Which sampling method divides the population into groups, then randomly selects some groups and includes all members from those groups in the sample?

Accepted Answer

Cluster sampling

Question 4

A researcher wants to ensure that their sample reflects the age distribution of the population. Which sampling method should they use?

Accepted Answer

Stratified sampling

Question 5

Which of the following is NOT a guideline for evaluating the credibility of a statistical study?

Accepted Answer

Assume the results are correct if they match your expectations.

Question 6

Which type of error occurs when a measurement consistently overestimates or underestimates the true value?

Accepted Answer

Systematic error

Question 7

A survey asks people at a shopping mall about their exercise habits. What type of sampling is this?

Accepted Answer

Convenience sampling

Question 8

Which of the following is a quantitative variable?

Accepted Answer

Number of books read in a month

Question 9

If a study reports that 'the average salary increased by 10%,' what is the correct formula to calculate the new average salary if the original average was $50,000?

Accepted Answer

$$50,000 + (50,000 	imes 0.10)$$

Question 10

A researcher selects every 10th person from a list of 1,000 employees. What sampling method is being used?

Accepted Answer

Systematic sampling

Question 11

Which of the following best describes an observational study?

Accepted Answer

Researchers observe and record data without influencing the subjects.

Question 12

A study finds a difference in test scores between two groups. Which of the following is the correct formula for the percentage difference if Group A scored 80 and Group B scored 100?

Accepted Answer

$$\frac{100 - 80}{100} 	imes 100\%$$

Question 13

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

Accepted Answer

Type of cuisine (Italian, Chinese, Mexican)

Question 14

A study uses a placebo to control for the psychological effects of receiving treatment. What is the main purpose of the placebo?

Accepted Answer

To control for the placebo effect and isolate the treatment's true effect.

Question 15

Which of the following best describes a systematic error?

Accepted Answer

An error that consistently skews results in one direction.

Question 16

A researcher wants to compare the effectiveness of two teaching methods. Which study design would provide the most reliable results?

Accepted Answer

Randomized controlled experiment

Question 17

Which of the following is a potential source of bias in a statistical study?

Accepted Answer

Allowing participants to self-select into groups

Question 18

If a measurement tool always reads 2 units higher than the true value, what type of error is this?

Accepted Answer

Systematic error

Question 19

Which of the following is an example of stratified sampling?

Accepted Answer

Dividing a population into age groups and randomly sampling from each group

Question 20

A study reports that 30% of participants improved after treatment. If there were 200 participants, how many improved?

Accepted Answer

$$200 	imes 0.30 = 60$$

Introduction to Statistics: Data Collection, Study Design, and Data Types

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