A Quiz That’ll Add To Your Knowledge Of Review Questions

Explanation
The statement "Economists design graphs to confuse people" is not true. Economists design graphs to visually represent data and economic concepts in a clear and concise manner. Graphs are used to help people understand complex economic relationships and trends. While some graphs may appear complicated, their purpose is to simplify information and make it easier to comprehend, rather than confuse people. Therefore, the correct answer is false.

Explanation
If the straight line on a two-variable graph slopes downward to the right, it indicates a negative relationship between the two variables. This means that as one variable increases, the other variable decreases. Therefore, the correct answer is False, as a negative relationship is opposite to a positive relationship.

Explanation
A dependent variable is a variable that is influenced or affected by changes in another variable. In this context, the statement is stating that a variable that changes as a result of a change in another variable is considered a dependent variable. This means that the dependent variable is dependent on the independent variable and its changes. Therefore, the correct answer is true.

Explanation
Economists do not always put the independent variable on the horizontal axis and the dependent variable on the vertical axis. The placement of variables on the axes depends on the specific context and purpose of the analysis. In some cases, economists may choose to reverse the placement of variables to better illustrate the relationship being studied. Therefore, it is not accurate to say that economists always follow a specific convention when plotting variables on a graph.

Explanation
Ceteris paribus means "all other things being equal" or "holding all other variables constant." It implies that while studying the effect of one variable, all other variables are assumed to remain unchanged. Therefore, the correct answer is False, as ceteris paribus assumes that other variables are not changing at the same time.

Explanation
The explanation for the given correct answer is that the slope of a straight line is calculated by dividing the vertical change (the difference in the y-coordinates of two points) by the horizontal change (the difference in the x-coordinates of the same two points). This ratio is written as rise over run, with the vertical change in the numerator and the horizontal change in the denominator. Therefore, it is true that the vertical change is in the numerator and the horizontal change is in the denominator when calculating the slope of a straight line.

Explanation
The given statement is true because a slope of 0.90 indicates a positive linear relationship between consumption and income. This means that for every $1 increase in income, there will be a $0.90 increase in consumption.

Explanation
The slope of a vertical line is undefined, regardless of the units chosen for either variable. The slope of a line is determined by the change in the y-coordinate divided by the change in the x-coordinate. However, for a vertical line, the change in the x-coordinate is always zero, resulting in a division by zero, which is undefined. Therefore, the choice of units for either variable does not affect the undefined slope of a vertical line.

Explanation
The statement is true because the slope of a line represents the rate of change between two points on the line. It measures how much the dependent variable changes for each unit increase in the independent variable. Therefore, the slope can be interpreted as the marginal change or the additional change that occurs for each additional unit of the independent variable.

Explanation
In a graph where price is on the vertical axis and quantity is on the horizontal axis, a straight line parallel to the horizontal axis would indicate that there is no relationship between price and quantity. This means that regardless of the changes in price, the quantity remains constant. Therefore, the statement "True" is correct.

Explanation
A line with an infinite slope in a two-variable graph is not parallel to the horizontal axis. A line with an infinite slope is a vertical line, which means it is perpendicular to the horizontal axis. Therefore, the correct answer is false.

Explanation
If income is independent of the quantity of snow, it means that the income does not change regardless of the amount of snow. In this case, the graph would show a horizontal line parallel to the horizontal axis, indicating that the income remains constant regardless of the quantity of snow. Therefore, the statement "True" is the correct answer.

Explanation
The given linear equation is y = 10 + 5x. The vertical intercept is the point where the line crosses the y-axis. In this equation, the y-intercept is 10, not 5. Therefore, the statement that the vertical intercept is 5 is incorrect. Hence, the correct answer is False.

Explanation
When a line is tangent to a nonlinear curve, it does not intersect the curve at a particular point. Instead, it touches the curve at only one point, known as the point of tangency. This point of tangency is where the slope of the line is equal to the slope of the curve at that specific point. Therefore, the statement is false.

Explanation
The slope of a straight line represents the rate of change of y with respect to x. In this case, the slope is 0.5, which means that for every unit increase in x, y increases by 0.5 units. The vertical intercept is the point at which the line intersects the y-axis, which is 5 in this case. So when x is 10, the line would have moved 10 units to the right from the y-axis, and since the slope is 0.5, y would have increased by 5 units (0.5 * 10). Therefore, when x is 10, y would also be 10, making the statement true.

Explanation
A slope of -4 for a straight line in a two-variable graph indicates that as one variable increases, the other variable decreases. This is because a negative slope represents a negative correlation between the two variables. Therefore, there is an inverse relationship between the two variables, supporting the statement that the answer is True.

Explanation
This statement is incorrect. In a cause-and-effect relationship, the independent variable (x) is the one that causes a change in the dependent variable (y). Therefore, a change in x would result in a change in y, not the other way around.

Explanation
If a straight line is tangent to a non-linear curve and has an upward slope, it means that the slope of the non-linear curve at that point is positive. This is because the tangent line represents the instantaneous rate of change of the curve at that specific point. If the tangent line has a positive slope, it indicates that the curve is increasing at that point, which means the slope of the curve is positive. Therefore, the statement is true.

Explanation
The slope of a straight line can be calculated using the formula (change in y)/(change in x). In this case, the change in y is 20-10 = 10, and the change in x is 8-13 = -5. Therefore, the slope is 10/-5 = -2. Since the given answer is False, it is correct because the slope is -2, not 2.

Explanation
The given linear equation y = -2 + 6x represents a straight line with a slope of 6 and a y-intercept of -2. When the value of x is 2, substituting it into the equation gives y = -2 + 6(2) = -2 + 12 = 10. Therefore, when x is 2, the value of y is indeed 10.