Q: Suppose a data set has $$Q_1 = 20$, Q_3$ = 40$$, and an observation at 5. According to the 1.5 × IQR rule, is 5 a potential outlier?

Yes, because $$5 \u003c Q_1$ - 1.5 \times IQR$$

Question 1

Which of the following is the best example of a categorical variable?

Accepted Answer

The favorite type of music of each student

Question 2

A researcher records the number of cars passing through an intersection each hour. What type of variable is this, and how should it be visualized?

Accepted Answer

Quantitative discrete; use a histogram

Question 3

Which of the following statements about histograms and bar graphs is TRUE?

Accepted Answer

Histograms are used for quantitative data, while bar graphs are used for categorical data.

Question 4

A distribution of exam scores is skewed to the right. Which of the following is most likely TRUE?

Accepted Answer

The mean is greater than the median.

Question 5

Given the following data set: 2, 3, 3, 4, 5, 5, 6, 7, what is the mode?

Accepted Answer

Both 3 and 5

Question 6

A sample of 8 values has been ordered from smallest to largest. Which formula gives the position of the median?

Accepted Answer

$$\frac{n+1}{2}$$

Question 7

A data set has a minimum value of 10, a first quartile ($$Q_1) of 15$$, a median of 20, a third quartile ($$Q_3) of 25$$, and a maximum of 40. What is the interquartile range (IQR)?

Accepted Answer

$$25 - 15 = 10$$

Question 8

Which of the following is a property of the standard deviation?

Accepted Answer

It is zero only when all observations are identical.

Question 9

A data set has $$n = 5$$ values: 2, 4, 6, 8, 10. What is the mean?

Accepted Answer

$$6$$

Question 10

Suppose a data set has $$Q_1 = 20$, Q_3$ = 40$$, and an observation at 5. According to the 1.5 × IQR rule, is 5 a potential outlier?

Accepted Answer

Yes, because $$5 \u003c Q_1$ - 1.5 	imes IQR$$

Question 11

A time plot is most appropriate for which of the following scenarios?

Accepted Answer

Displaying the number of daily hospital admissions over a year

Question 12

Which of the following best describes a distribution that is symmetric and unimodal?

Accepted Answer

The mean and median are approximately equal.

Question 13

If a histogram of a data set shows a long tail to the left, how is the distribution described?

Accepted Answer

Skewed to the left

Question 14

A company wants to compare the salaries of employees in two departments. Which graphical summary is most appropriate for side-by-side comparison?

Accepted Answer

Box plot

Question 15

Which of the following is NOT a requirement for a good data table or graph?

Accepted Answer

Bars colored according to the mean value

Question 16

A data set of 100 values is approximately bell-shaped with mean $$\mu = 50$$ and standard deviation $$\sigma = 5. $$According to the Empirical Rule, about how many values are expected to fall between 45 and 55?

Accepted Answer

About 68

Question 17

Which of the following is a key advantage of a stem-and-leaf plot over a histogram?

Accepted Answer

It retains the actual data values.

Question 18

A pictogram is considered misleading when:

Accepted Answer

The area of the pictures does not correspond to the data values.

Question 19

A student scores at the 90th percentile on a standardized test. What does this mean?

Accepted Answer

The student scored higher than 90% of test takers.

Question 20

Which of the following is TRUE about the mode?

Accepted Answer

It is the value that occurs most frequently in the data set.

Exploring Data with Graphs and Numerical Summaries (STA 215, Chapter 2)

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