Question 1

Which of the following best describes a population in statistics?

Accepted Answer

All individuals or items that are the subject of a statistical study.

Question 2

A survey asks students how many hours they study per week. What type of variable is this?

Accepted Answer

Quantitative (numerical) variable

Question 3

Which sampling method is most likely to introduce bias if a teacher only surveys students who volunteer to participate?

Accepted Answer

Volunteer sampling

Question 4

Given the following frequency distribution, what is the class midpoint for the class 20-29?

Class: 10-19, 20-29, 30-39
Frequency: 5, 8, 7

Accepted Answer

$$\frac{20+29}{2}$$

Question 5

A histogram is used to display which type of data?

Accepted Answer

Quantitative (numerical) data

Question 6

Which of the following is a misleading conclusion when interpreting survey results?

Accepted Answer

Ignoring nonresponse bias

Question 7

If the mean of a sample is 50 and the standard deviation is 5, what is the z-score for a value of 60?

Accepted Answer

$$z = \frac{60-50}{5}$$

Question 8

Which measure of center is most appropriate for a highly skewed distribution of income?

Accepted Answer

Median

Question 9

What is the formula for the sample variance using the shortcut method?

Accepted Answer

$$s^2$$ = \frac{n(\sum $$x^2$$) - (\sum $$x)^2$$}{n(n-1)}$$

Question 10

A boxplot is a graphical representation of which summary?

Accepted Answer

5-number summary

Question 11

If a dataset has a mean of 100 and a standard deviation of 15, what range would include approximately 95% of the data according to the Empirical Rule?

Accepted Answer

$$100 \pm 2 	imes 15$$

Question 12

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

Accepted Answer

Temperature of a local pool

Question 13

What is the interquartile range (IQR) formula?

Accepted Answer

$$IQR = Q_3$ - Q_1$

Question 14

A researcher wants to estimate the average commute time for employees by randomly selecting every 10th employee from a list. Which sampling method is this?

Accepted Answer

Systematic sampling

Question 15

Which of the following is NOT a property of a frequency distribution?

Accepted Answer

Mode

Question 16

If the sample mean is $$\bar{x} = 25$$ and the sample size is $$n = 10$$, what is the sum of all sample values?

Accepted Answer

$$\sum x = 250$$

Question 17

Which of the following best describes an ordinal variable?

Accepted Answer

A variable with values that can be ranked but not measured numerically.

Question 18

A pie chart is most appropriate for displaying which type of data?

Accepted Answer

Categorical data

Question 19

If a value is more than 2 standard deviations above the mean, it is considered:

Accepted Answer

Statistically significant high value

Question 20

Which formula is used to find the location of a percentile in a ranked dataset?

Accepted Answer

$$L = \frac{k}{100} 	imes n$$

Statistics Unit 1: Foundations, Data, and Descriptive Analysis (Chapters 1–3)

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