Q: How is the class midpoint calculated for a class interval?

$$\text{Class midpoint} = \frac{\text{Lower class limit} + \text{Upper class limit}}{2}$$

Q: A frequency distribution table has the following frequencies: 60, 35, 22, 18, 15. What is the cumulative frequency for the third class?

$$\text{Cumulative frequency} = 117$$

Q: What is the sum of the relative frequencies in a relative frequency distribution?

$$\text{Sum} \approx 1 (or$$ $$100\%)$$

Q: Given the following frequency distribution: Class intervals: 0–10, 10–20, 20–30, 30–40, 40–50. Frequencies: 2, 3, 6, 4, 2. What is the relative frequency for the 20–30 class?

$$\text{Relative frequency} = \frac{6}{17} \approx 0.353$$

Question 1

Which of the following best describes a frequency distribution?

Accepted Answer

A table that shows how data are partitioned among several categories by listing the categories along with the number (frequency) of data values in each.

Question 2

Given the class intervals 15–25, 25–35, 35–45, 45–55, and 55–65, what is the class width?

Accepted Answer

$$	ext{Class width} = 10$$

Question 3

How is the class midpoint calculated for a class interval?

Accepted Answer

$$	ext{Class midpoint} = \frac{	ext{Lower class limit} + 	ext{Upper class limit}}{2}$$

Question 4

A frequency distribution table has the following frequencies: 60, 35, 22, 18, 15. What is the cumulative frequency for the third class?

Accepted Answer

$$	ext{Cumulative frequency} = 117$$

Question 5

Which type of graph is most appropriate for displaying categorical data such as blood types?

Accepted Answer

Pie chart

Question 6

What is the sum of the relative frequencies in a relative frequency distribution?

Accepted Answer

$$	ext{Sum} \approx 1 (or$$ $$100\%)$$

Question 7

Which of the following best describes a histogram?

Accepted Answer

A graph consisting of bars of equal width drawn adjacent to each other, representing frequencies of quantitative data.

Question 8

If a histogram shows frequencies that start low, increase to a maximum, then decrease symmetrically, what type of distribution is this?

Accepted Answer

Normal distribution

Question 9

Which plot is best for visualizing trends in data collected over time, such as monthly sales?

Accepted Answer

Time-series graph

Question 10

A scatterplot shows a downward trend between two variables. What does this indicate about their correlation?

Accepted Answer

Negative linear correlation

Question 11

Which of the following statements about correlation is correct?

Accepted Answer

Correlation does not imply causation.

Question 12

Given the following frequency distribution: Class intervals: 0–10, 10–20, 20–30, 30–40, 40–50. Frequencies: 2, 3, 6, 4, 2. What is the relative frequency for the 20–30 class?

Accepted Answer

$$	ext{Relative frequency} = \frac{6}{17} \approx 0.353$$

Question 13

In a categorical frequency distribution for trust in Internet information, which category would have the highest frequency if most people trust in most of what they read?

Accepted Answer

M

Question 14

What is the formula for the Pearson correlation coefficient $$r$$?

Accepted Answer

$$r = \frac{\sum (x_i - \bar{x})(y_i - \bar{y})}{\sqrt{\sum (x_i - \bar{x})^2$ \sum (y_i - \bar{y})^2$}}$$

Question 15

Which chart is most useful for identifying the most common cause of fatal plane crashes?

Accepted Answer

Pie chart

Question 16

If you want to compare the distribution of commute times between two cities, which type of frequency distribution should you use?

Accepted Answer

Relative frequency distribution

Question 17

What is the regression equation for a linear relationship between $$x$$ and $$y$$?

Accepted Answer

$$y = a + bx$$

Question 18

Which of the following is NOT a feature of a histogram?

Accepted Answer

Bars are separated by gaps to show categories.

Question 19

A dotplot is most similar to which other type of graph?

Accepted Answer

Histogram

Exploring Data with Tables and Graphs: Frequency Distributions, Graphical Summaries, and Correlation

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