Difficulty: Introductory | Prerequisites: None.
This section tests whether you can read graphs, identify variables, describe trends, and explain what data means in context. The exam uses three datasets: car depreciation (line graph), pulse rate during exercise (line graph), and a soda flavour survey (pie chart). You need to know which graph type suits which kind of data, and how to draw real-world conclusions from the numbers.
Independent variable
The variable that is manipulated or chosen by the researcher. It stands alone and is not changed by other variables in the experiment. Plotted on the x-axis (horizontal).
Think of it as the "input" or "what you control," such as time or temperature.
Dependent variable
The variable that is measured or observed. Its value changes in response to the independent variable. Plotted on the y-axis (vertical).
In simple terms, it is the "output" or "what happens as a result."
Line graph
A graph that uses points connected by lines to show how a variable changes over a continuous period of time. Best for tracking trends.
Bar graph
A graph that uses rectangular bars to compare data across different groups or to show changes over time. Versatile for both comparison and tracking.
Pie chart
A circular graph divided into slices to show the relative sizes of different categories as parts of a whole at a single point in time.
Think of it as a snapshot of "who has what share."
Scatter plot
A graph that uses individual data points to show the relationship between two numerical variables. Best for identifying correlations.
Depreciation
The decrease in value of an asset over time. In the exam context, the car in Graph A depreciates from $20,470 to under $5,000 across six years.
In simple terms, it is how much value something loses as it ages.
Data: 2016: $20,470 / 2017: $18,570 / 2018: $16,670 / 2019: $11,770 / 2020: $9,870 / 2021: $5,170 / 2022: under $5,000
Independent variable (x-axis): Year
Dependent variable (y-axis): Value in dollars
Overall trend: Consistent, sharp decrease. The car loses more than 75% of its initial value across six years.
Biggest single-year drop: 2018 to 2019, from $16,670 to $11,770 (a loss of nearly $5,000). Another substantial decline occurs between 2020 and 2021 ($9,870 to $5,170).
What it means: The car is a rapidly depreciating asset and a poor long-term financial investment in terms of resale value.
Data: 0 min: 70 bpm / 2 min: 95 bpm / 3 min: 121 bpm (peak) / 4 min: 110 bpm
Independent variable (x-axis): Time in minutes
Dependent variable (y-axis): Pulse rate in beats per minute
Key detail: The pulse rate peaks at 3 minutes (121 bpm), then drops to 110 bpm at 4 minutes.
What the 3-to-4-minute drop indicates: The participant has either reduced exercise intensity or entered a recovery phase after reaching maximum exertion.
Data: Cherry Soda: largest slice / Mountain Dew: 5% / Vanilla Mint: 6% / Other categories: Ginger, Other, Mountain Dew
Why a pie chart: The data shows parts of a whole (total survey responses split by preference) at a single point in time.
Key detail: Mountain Dew has the lowest recorded percentage at 5%. A beverage company should avoid launching a product similar to Mountain Dew, since it indicates the lowest market demand.
Line graph: Best for showing how a variable changes over a continuous period. Use when the x-axis is time or another continuous sequence.
Pie chart: Best for comparing parts of a whole at a single point in time. Use when you want to show relative shares or proportions.
Bar graph: Best for comparing data across different groups or tracking changes over time. The most versatile option (Q14, answer C).
Scatter plot: Best for showing the relationship or correlation between two numerical variables.
Students often mix up independent and dependent variables. A quick check: the independent variable is what you set or choose (time, dose, temperature); the dependent variable is what you measure as a result.
A pie chart cannot show change over time. If someone asks about trends, the answer is a line graph or bar graph, never a pie chart.
Students sometimes identify the largest drop in the car data as 2016 to 2017 because it is the first decline. The largest single-year drop is 2018 to 2019 (nearly $5,000).
In Graph B, the pulse rate drop from 3 to 4 minutes does not mean the exercise stopped. It indicates a reduction in intensity or the beginning of recovery.
Q3 (10 marks) asks for a full analysis of Graph A: trend, biggest drop, and financial implications. Cite specific dollar figures.
Q5 (3 marks) directly asks you to define independent and dependent variables and name their axes.
Q9 (3 marks) asks when to use a pie chart versus a line graph. Answer using Graph A (line) and Graph C (pie) as examples.
Q14 (3 marks, multiple choice) asks which graph type is best for comparing groups or tracking changes over time. Answer: bar graph (C).
Q15 (2 marks, multiple choice) asks for the dependent variable in Graph B. Answer: pulse rate (C).
Q17 (2 marks, multiple choice) asks for Mountain Dew's percentage. Answer: 5% (C).
Q20 (4 marks) asks you to explain the pulse rate drop from 3 to 4 minutes.
Q23 (4 marks) asks you to interpret the soda survey and advise which flavour to avoid.
Fill in the blank: The independent variable goes on the ______ axis and the dependent variable goes on the ______ axis. (x / horizontal; y / vertical)
True or False: A pie chart is the best way to track how a car's value changes over time. (False. Use a line graph.)
Fill in the blank: The car's largest single-year value drop occurred between ______ and ______. (2018; 2019)
True or False: In Graph B, the dependent variable is the time in minutes. (False. It is the pulse rate in bpm.)
Fill in the blank: Mountain Dew accounted for ______% of the soda survey preferences. (5%)
Q: Analyse the Value of Car line graph. Describe the overall trend, identify the period with the most significant drop, and explain what this suggests about the car as a financial asset.
A: The overall trend is a consistent, sharp decrease from $20,470 in 2016 to under $5,000 in 2022. The most significant drop occurred between 2018 ($16,670) and 2019 ($11,770), a loss of nearly $5,000 in a single year. This data suggests the car is a rapidly depreciating asset, losing more than 75% of its initial value within six years, making it a poor long-term financial investment for resale.
Q: Describe the change in pulse rate from 3 minutes to 4 minutes and explain what it indicates about the participant's physical state.
A: The pulse rate decreased from 121 bpm (peak) to 110 bpm. This indicates the participant has either reduced exercise intensity or entered a recovery phase after reaching maximum exertion at the 3-minute mark.
Q: If a beverage company wanted to launch a new flavour based on the soda survey, which flavour should they avoid, and why?
A: They should avoid launching a product similar to Mountain Dew, which holds the lowest recorded preference at 5%. Compared to Cherry Soda (the largest slice), Mountain Dew represents the least popular specific category, indicating low market demand.
Graph interpretation links to the argumentative essay material because Q3 (the car analysis) is structured as an analytical essay response: describe, identify, explain. The same describe-identify-explain pattern applies to Q20 (pulse rate) and Q23 (soda survey). Being comfortable with data also helps when writing rebuttals in the AI debate, where you cite Stanford or ISTE research as evidence.
Related Terms / Search Tags: graphical data interpretation, line graph, bar graph, pie chart, scatter plot, independent variable, dependent variable, x-axis, y-axis, depreciation, asset value, pulse rate, exercise physiology, soda survey, parts of a whole, trends over time, ENL 5505, Periods in English Literature, FIU