Question 1

Which of the following best describes the Area Principle in data visualization?

Accepted Answer

The area occupied by a part of the graph should correspond to the magnitude of the value it represents.

Question 2

A researcher wants to display the distribution of blood types (A, B, AB, O) in a hospital. Which graphical display is most appropriate?

Accepted Answer

Bar chart

Question 3

Which of the following is NOT a correct step when calculating the median for a data set with an even number of values?

Accepted Answer

Use the value with the highest frequency as the median.

Question 4

A histogram of monthly expenditures for a group of customers is highly skewed to the right with one value far above the rest. Which measure of center is most appropriate to report?

Accepted Answer

Median

Question 5

Which formula correctly calculates the sample variance $$s^2$$ for a set of $$n$$ values $$y_1$$, $$y_2$$, ..., y_n$$ with mean $$\bar{y}$$?

Accepted Answer

$$s^2$$ = \frac{1}{n-1} \sum_{i=1}^n (y_i - \bar{y}$$)^2$$

Question 6

A distribution of exam scores is symmetric and unimodal. Which summary statistics should you report?

Accepted Answer

Mean and standard deviation

Question 7

Which of the following statements about outliers is TRUE?

Accepted Answer

Outliers can sometimes be the most important data values.

Question 8

A frequency table for Titanic passengers shows the following counts: First: 324, Second: 285, Third: 710, Crew: 889. What is the relative frequency (percentage) of Third class passengers? (Round to two decimal places)

Accepted Answer

32.16%

Question 9

Which of the following is a characteristic of a uniform distribution?

Accepted Answer

All bins have the same or nearly the same frequency.

Question 10

If a histogram has a longer tail on the left side of the mode, how is the distribution described?

Accepted Answer

Skewed left

Question 11

Which of the following is NOT an appropriate use of a histogram?

Accepted Answer

Displaying the distribution of a categorical variable

Question 12

A data set has Q1 = 22 and Q3 = 37. What is the interquartile range (IQR)?

Accepted Answer

$$IQR = 15$$

Question 13

Which of the following is a reason to prefer the median over the mean as a measure of center?

Accepted Answer

The data contain outliers or are skewed.

Question 14

A bar chart is used to display which type of variable?

Accepted Answer

Categorical

Question 15

Which of the following is the correct formula for the standard deviation $$s of a $$sample?

Accepted Answer

$$s = \sqrt{\frac{1}{n-1} \sum_{i=1}^n (y_i - \bar{y})^2$}$$

Question 16

A financial analyst collects the commute times (in minutes) for 100 employees. The mean is 44.98 min, the median is 37.5 min, and the standard deviation is 30.19 min. What does the difference between the mean and median suggest about the distribution?

Accepted Answer

The distribution is skewed right.

Question 17

Which of the following is a potential drawback of using the range as a measure of spread?

Accepted Answer

It only uses the two most extreme values.

Question 18

When summarizing a distribution that is highly skewed with outliers, which combination of statistics is most appropriate?

Accepted Answer

Median and interquartile range (IQR)

Question 19

Which of the following is NOT a recommended practice when analyzing data?

Accepted Answer

Report too many decimal places in your summary statistics.

Chapter 2: Displaying and Describing Data – Introductory Statistics Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard