Q: If 75 out of 300 people in a survey like a new product, what percentage of people like the product?

$$\frac{75}{300} \times 100 = 25\%$$

Q: Change the fraction $$\frac{3}{8} to a $$percent.

$$\frac{3}{8} = 0.375 \times 100 = 37.5\%$$

Q: A study finds that 10 out of 40 people improved after a treatment. What percent improved?

$$\frac{10}{40} \times 100 = 25\%$$

Question 1

Which of the following best describes a population in the context of a statistics study?

Accepted Answer

The complete collection of ALL measurements or data being considered.

Question 2

A researcher wants to know the average weight of all students at a university. Instead of measuring everyone, she measures the weight of 50 randomly selected students. What is the 50 students called?

Accepted Answer

Sample

Question 3

Which of the following is an example of a voluntary response sample?

Accepted Answer

Allowing people to choose whether or not to participate in an online poll.

Question 4

A study finds that a new medication reduces cholesterol by an average of 1 mg/dL, with a p-value of 0.01. Which of the following is true?

Accepted Answer

The result is statistically significant but may not be practically significant.

Question 5

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

Accepted Answer

Correlation does not imply causation.

Question 6

A survey finds that 40% of 2,500 people prefer tea over coffee. How many people prefer tea?

Accepted Answer

$$0.40 	imes 2,500 = 1,000$$

Question 7

If 75 out of 300 people in a survey like a new product, what percentage of people like the product?

Accepted Answer

$$\frac{75}{300} 	imes 100 = 25\%$$

Question 8

Convert the decimal $$0.085 to a $$percent.

Accepted Answer

$$0.085 	imes 100 = 8.5\%$$

Question 9

Change the fraction $$\frac{3}{8} to a $$percent.

Accepted Answer

$$\frac{3}{8} = 0.375 	imes 100 = 37.5\%$$

Question 10

Convert $$2.5\% to a $$decimal.

Accepted Answer

$$2.5 \div 100 = 0.025$$

Question 11

A survey asks, 'Don't you agree that exercise is important for health?' What is the main issue with this question?

Accepted Answer

It is a loaded question, which can bias responses.

Question 12

A researcher collects data by asking people to self-report their income. What potential pitfall is most relevant here?

Accepted Answer

Sample data reported instead of measured.

Question 13

Which of the following best describes a census?

Accepted Answer

Collecting data from every member of the population.

Question 14

A survey finds that 0.6% of people have a rare blood type. Express this as a decimal.

Accepted Answer

$$0.6 \div 100 = 0.006$$

Question 15

A study finds that 10 out of 40 people improved after a treatment. What percent improved?

Accepted Answer

$$\frac{10}{40} 	imes 100 = 25\%$$

Question 16

Which of the following is an example of practical significance without statistical significance?

Accepted Answer

A new teaching method increases test scores by 20 points, but the result could easily occur by chance.

Question 17

A survey asks, 'Would you say that pollution from cars is more harmful than pollution from factories?' If the order of 'cars' and 'factories' is switched in the question, what effect might this have?

Accepted Answer

The order of the words can influence which option people choose.

Question 18

A researcher collects data from only 5 people in a city of 1 million. What is the main issue with this sample?

Accepted Answer

The sample size is too small to be reliable.

Question 19

Which of the following is an example of missing data?

Accepted Answer

People who are embarrassed about their weight choose not to participate in a weight survey.

Question 20

A study finds that 95 out of 100 coin flips are tails. What does this result suggest?

Accepted Answer

The result is statistically significant because it is very unlikely to occur by chance.

Section 1.1: Statistical and Critical Thinking – Introductory Statistics Study Notes

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