Q: A dataset has the following five-number summary: Min = 2, Q1 = 5, Median = 8, Q3 = 12, Max = 20. What is the upper bound for outliers using the 1.5 × IQR rule?

Upper Bound = Q3 + 1.5 \times IQR = 12 + 1.5 \times (12 - 5) = 12 + 10.5 = 22.5

Question 1

Which of the following best describes a parameter in statistics?

Accepted Answer

A numerical summary that describes an entire population.

Question 2

A hospital records the blood types of all patients admitted in a month. Which level of measurement is used for blood type?

Accepted Answer

Nominal

Question 3

A researcher wants to estimate the average commute time for employees at a large company. She randomly selects 10 departments and surveys every employee in those departments. Which sampling method is she using?

Accepted Answer

Cluster sampling

Question 4

Which of the following variables is quantitative and continuous?

Accepted Answer

Temperature measured in degrees Celsius

Question 5

A survey asks participants to rate their satisfaction as 'Poor', 'Fair', 'Good', or 'Excellent'. What is the level of measurement for this variable?

Accepted Answer

Ordinal

Question 6

Given the sample data: 3, 7, 7, 10, 12. What is the sample mean ($$\bar{x}$$)?

Accepted Answer

$$\bar{x} = \frac{3 + 7 + 7 + 10 + 12}{5} = 7.8$$

Question 7

A frequency table shows the following counts for favorite ice cream flavors: Vanilla (20), Chocolate (30), Strawberry (10). What is the relative frequency for Chocolate?

Accepted Answer

$$\frac{30}{60} = 0.5$$

Question 8

Which graphical representation is most appropriate for displaying the distribution of ages (in years) of patients in a clinic?

Accepted Answer

Histogram

Question 9

A dataset has a mean of 50 and a standard deviation of 8. What is the z-score for a value of 66?

Accepted Answer

$$z = \frac{66 - 50}{8} = 2$$

Question 10

Which measure of central tendency is most resistant to extreme values (outliers)?

Accepted Answer

Median

Question 11

A sample of exam scores is: 60, 70, 80, 90, 100. What is the sample variance ($$s^2$$)?

Accepted Answer

$$s^2$$ = \frac{$$(60-80)^2$$ + $$(70-80)^2$$ + $$(80-80)^2$$ + $$(90-80)^2$$ + $$(100-80)^2$$}{5-1} = \frac{400 + 100 + 0 + 100 + 400}{4} = \frac{1000}{4} = 250$$

Question 12

A dataset is ordered as follows: 5, 8, 12, 15, 20, 22, 25, 30. What is the interquartile range (IQR)?

Accepted Answer

IQR = Q3 - Q1 = 25 - 12 = 13

Question 13

Which of the following is NOT a valid method for detecting outliers in a dataset?

Accepted Answer

Calculating the mean and mode

Question 14

A company wants to survey employees about job satisfaction. They select every 10th employee from an alphabetical list. What sampling method is this?

Accepted Answer

Systematic sampling

Question 15

Which of the following best describes a histogram?

Accepted Answer

A graph for quantitative data with touching bars representing class intervals

Question 16

A dataset has the following five-number summary: Min = 2, Q1 = 5, Median = 8, Q3 = 12, Max = 20. What is the upper bound for outliers using the 1.5 × IQR rule?

Accepted Answer

Upper Bound = Q3 + 1.5 	imes IQR = 12 + 1.5 	imes (12 - 5) = 12 + 10.5 = 22.5

Question 17

Which of the following is an example of a convenience sample?

Accepted Answer

Surveying students who happen to be in the cafeteria at lunchtime

Question 18

A stem-and-leaf display is most useful for which type of data?

Accepted Answer

Quantitative data, showing individual values

Question 19

A dataset is skewed right. Which statement is most likely true about its mean and median?

Accepted Answer

Mean \u003e Median

Question 20

A sample has values: 5, 7, 9, 11, 13. What is the z-score for x = 13 if $$\bar{x} = 9$$ and $$s = 3.16$$?

Accepted Answer

$$z = \frac{13 - 9}{3.16} = 1.27$$

Introductory Statistics Study Guide: Chapters 1–3 (Pearson)

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