Scientific Passages: Interpreting Data from Graphs & Tables

Core Concepts

Essential skills for reading and interpreting data presented in charts, graphs, and tables, a common task on the SAT and ACT science sections.

Scientific Passages: Interpreting Data from Graphs & Tables

1 of 12

What is the very first step you should take when encountering a graph or table in a passage?

Read the title, the axis labels (for graphs), the column headers (for tables), and any keys or legends. This tells you what information is being presented and how it is organized.

On a typical scientific graph, which axis represents the independent variable?

The horizontal axis, or x-axis, usually represents the independent variable—the factor that was manipulated by the researcher.

On a typical scientific graph, which axis represents the dependent variable?

The vertical axis, or y-axis, usually represents the dependent variable—the factor that was measured as the outcome of the experiment.

How do you identify a 'direct relationship' (or positive correlation) on a line graph?

A Cartesian coordinate graph showing a positive correlation, where a curved line slopes upward from left to right as the values along the x-axis and y-axis both increase.

The line will slope upwards from left to right. This indicates that as the independent variable (on the x-axis) increases, the dependent variable (on the y-axis) also tends to increase.

How do you identify an 'inverse relationship' (or negative correlation) on a line graph?

A line graph showing an inverse relationship, with a straight line sloping downward from left to right to demonstrate that as X increases, Y decreases.

The line will slope downwards from left to right. This indicates that as the independent variable (on the x-axis) increases, the dependent variable (on the y-axis) tends to decrease.

What is the crucial difference between 'results' and 'conclusions'?

Results are the direct, objective findings and raw data from the experiment (e.g., 'Group A grew 2 cm taller'). Conclusions are the researcher's interpretation of those results (e.g., 'Therefore, the fertilizer promotes growth'). Data questions focus on results.

If a question asks you to find evidence in a figure to support a claim, what should you do?

Locate the specific data points, trends, or comparisons on the graph or table that directly demonstrate the claim. Avoid making inferences; stick to what the data explicitly shows.

What do 'error bars' on a graph typically represent?

A line graph on an X-Y axis displaying data points connected by a curved line, with vertical error bars through each point representing measurement uncertainty or variability.

Error bars indicate the uncertainty or variability in a measurement. Larger error bars mean more variability or less certainty in that data point. If error bars between two groups overlap significantly, the difference between them may not be statistically significant.

When analyzing a table, what is an efficient way to find the information you need?

First, read the title and column/row headers. Then, scan the specific row and column that correspond to the conditions mentioned in the question to locate the exact data value.

What does it mean to 'interpolate' data from a graph?

A Cartesian coordinate graph illustrating data interpolation, showing a red point estimated along a line segment between two known black data points.

To estimate a value that lies *between* two known data points on a graph. For example, if you have points for time \(t=2\) and \(t=4\), you would interpolate to estimate the value at \(t=3\).

What is an 'outlier' in a data set?

A scatter plot on an XY coordinate plane showing a tight cluster of black data points with a single red data point located far away in the upper right, illustrating a statistical outlier.

A data point that lies significantly far from the other points or deviates from the general trend. It could be due to experimental error or represent a rare occurrence.

What does it mean to 'extrapolate' data from a graph?

A coordinate graph demonstrating extrapolation, with a solid line connecting known data points up to (4, 3) and a dashed line extending beyond to estimate a new data point at (5, 4).

To estimate a value that lies *beyond* the range of the collected data by extending the trend line. Extrapolation is less reliable than interpolation because the trend may not continue.

Scientific Passages: Interpreting Data from Graphs & Tables

Confirm Action

Prompt