Question 1

A line chart is created by plotting the values of the variable on the vertical axis and the time periods on the horizontal axis.

Accepted Answer

This statement is true. A line chart is a graphical representation of data that is created by plotting the values of a variable on the vertical axis and the time periods on the horizontal axis. Line charts are commonly used to visualize trends over time.

Question 2

Data for calories and salt content (milligrams of sodium) in 17 brands of meat hot dogs are shown in the scatter diagram below. According to this diagram, it appears that hot dogs that are high in sodium are generally low in calories, and hot dogs with low sodium are generally high in calories.

Accepted Answer

The answer of Data for calories and salt content (milligrams...

Question 3

-The line chart below shows cucumber prices fluctuated from $2.00 per pound to over $4.50 per pound during the year.

Accepted Answer

The answer of 
-The line chart below shows cucumber prices...

Question 4

The graph below represents a line graph.

Accepted Answer

The answer of The graph below represents a line graph....

Question 5

Experience shows that few students hand in their statistics exams early; most prefer to hand them in near the end of the test period. This means the time taken by students to write exams is positively skewed.

Accepted Answer

The statement describes a situation where most students hand in their exams towards the end of the test period, which suggests a concentration of data points at the higher end of the time scale. This would actually indicate a negatively skewed distribution, as the "tail" of the distribution is towards the lower end (few students handing in early). Positive skewness would mean the tail is on the higher end, opposite of what is described.

Question 6

The two most important characteristics revealed by the scatter diagram are the strength and direction of the linear relationship.

Accepted Answer

The scatter plot displays the strength and direction of the linear relationship between two variables. The strength of the relationship can be determined by the clustering of points around a line of best fit, while the direction can be determined by the slope of the line. Therefore, both characteristics are important and can be revealed by a scatter diagram.

Question 7

The scatter diagram below depicts data with a negative linear relationship.

Accepted Answer

A negative linear relationship means that as one variable increases, the other decreases. This can be seen in the scatter diagram as the points fall on a downwards sloping line.

Question 8

Correlation implies causation.

Accepted Answer

Correlation simply means that two variables are related or associated in some way. It does not necessarily mean that one variable causes the other. Correlation is necessary but not sufficient for causation. Other factors, such as confounding variables, need to be considered to establish causation.

Question 9

When two variables are linearly related, and tend to move in opposite directions, we describe the nature of their association as a negative linear relationship.

Accepted Answer

When two variables tend to move in opposite directions, we call it a negative relationship. When two variables are linearly related, this means that their relationship can be represented by a straight line on a scatter plot. Therefore, a negative linear relationship implies that as one variable increases, the other variable decreases in a linear fashion.

Question 10

The graph below is an example of a histogram.

Accepted Answer

The answer of The graph below is an example of...

Question 11

A modal class is the class with the largest number of observations.

Accepted Answer

This statement is true. A modal class is determined by finding the class interval with the highest frequency in a dataset, thus it represents the class with the largest number of observations.

Question 12

The sum of cumulative relative frequencies always equals 1.

Accepted Answer

The answer of The sum of cumulative relative frequencies always...

Question 13

-The line chart below shows tomato prices each month from January (month 1) to December last year ($ per pound). By looking at this chart you can see the lowest tomato prices occurred in July.

Accepted Answer

The answer of 
-The line chart below shows tomato prices...

Question 14

If two variables have a strong linear relationship, that means one variable is causing the other variable to go up or down.

Accepted Answer

A strong linear relationship between two variables means that they are correlated, but it doesn't necessarily mean that one variable is causing the other. Correlation does not equal causation, and there may be other factors at play that influence both variables.

Question 15

The graphical technique used to describe the relationship between two interval variables is the scatter diagram.

Accepted Answer

The scatter diagram is a graphical technique that displays the relationship between two interval variables.

Question 16

The two most important characteristics to examine in a scatter diagram are the number of possible categories for X and Y and the number of observations in each category.

Accepted Answer

The two most important characteristics to examine in a scatter diagram are the overall pattern or relationship between X and Y and the strength of the relationship or correlation between X and Y. The number of categories and observations may also be important, but they are not the most important characteristics to examine.

Question 17

The first scatter diagram below shows a stronger linear relationship than the second scatter diagram. (Assume the scales on both scatter diagrams are the same.)

Accepted Answer

In the first scatter diagram, the points are more tightly clustered around the line of best fit, indicating a stronger linear relationship, whereas in the second scatter diagram, the points are more spread out and do not appear to have a clear linear relationship.

Question 18

Time series data are often graphically depicted on a line chart, which is a plot of the variable of interest over time.

Accepted Answer

True, time series data are commonly displayed using a line chart to show the variable's trend over time.

Question 19

If we draw a straight line through the points in a scatter diagram and most of the points fall close to the line, there must be a positive relationship between the two variables.

Accepted Answer

A straight line through points in a scatter diagram indicates a linear relationship, which can be either positive or negative, depending on the direction of the slope of the line.

Question 20

A line chart that is flat shows no fluctuation in the variable being presented.

Accepted Answer

A flat line chart means that the variable is remaining constant or not changing, showing no fluctuation.

Quiz 2: Graphical and Tabular Descriptive Techniques