Question 1

Correlation implies causation.

Accepted Answer

Correlation refers to a relationship between two variables, but it does not necessarily imply that one variable causes the other. There may be other factors influencing the relationship, and further research is needed to establish causation.

Question 2

The graph below is an example of a histogram.

Accepted Answer

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

Question 3

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 4

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

Accepted Answer

The scatter diagram is used to visually represent the relationship between two variables. The strength of the relationship is indicated by how closely the points on the scatter diagram resemble a straight line, while the direction of the relationship is indicated by whether the line slopes upwards from left to right or downwards from left to right. Therefore, the two most important characteristics revealed by the scatter diagram are indeed the strength and direction of the linear relationship.

Question 5

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 6

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

Accepted Answer

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

Question 7

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 are linearly related and they tend to move in opposite directions, the correlation coefficient between them will be negative, indicating a negative linear relationship.

Question 8

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 description suggests that most students take a longer time, clustering towards the end of the test period, which would indicate a right-skewed (positively skewed) distribution for the start times, but for the duration, it suggests a concentration of longer times, not necessarily a skewed distribution of duration itself.

Question 9

The sum of cumulative relative frequencies always equals 1.

Accepted Answer

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

Question 10

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

Accepted Answer

This is true according to the definition of a modal class.

Question 11

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

Accepted Answer

Line charts are commonly used to display time series data.

Question 12

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 the points in a scatter diagram indicates a linear relationship, which can be either positive or negative depending on the direction of the slope. If the slope is upward, it's positive; if downward, it's negative.

Question 13

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

Accepted Answer

The answer of The scatter diagram below depicts data with...

Question 14

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

Accepted Answer

A flat line chart shows that the variable remains constant over time, with no fluctuations.

Question 15

The graph below represents a line graph.

Accepted Answer

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

Question 16

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

The answer of The first scatter diagram below shows a...

Question 17

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 is the correct definition of a line chart.

Question 18

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 does not necessarily mean that one variable is causing the other variable to go up or down. Correlation does not imply causation.

Question 19

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 relationship between X and Y (i.e. whether they are positively, negatively, or not correlated) and the overall pattern of the points (i.e. whether there are any outliers or clusters). The number of possible categories for X and Y and the number of observations in each category are not as important in evaluating the scatter diagram.

Question 20

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...

Quiz 2: Graphical and Tabular Descriptive Techniques