GRE data analysis strategies
GRE data analysis tests statistics (mean, median, mode, range, standard deviation), probability, and data interpretation from graphs, charts, and tables. These strategies cover reading the data before computing, the trap of misreading the axis or scale, and a worked example you can follow step by step.
The core principle
Read the data before you compute. Every data interpretation question starts with a graph, table, or chart. Before you touch a calculation, read the title, the axis labels, the units, and the legend. Know what each column or bar represents and what scale the chart uses. A calculation on the wrong axis or the wrong unit produces the right-looking answer that the test writers put in the choices.
Mean versus median: know the difference
The mean is the average: sum the values and divide by the count. The median is the middle value when the data is sorted. A single outlier pulls the mean up but barely moves the median. If a question says the mean is higher than the median, the distribution is skewed right by a high outlier. If the mean is lower, a low outlier pulls it down. Knowing this relationship lets you answer questions without computing either value.
The most common trap
Misreading the axis or the scale
The bar chart shows revenue in thousands of dollars. You read the value 50 and compute 50 dollars instead of 50,000. Or the axis starts at 40 instead of 0, so the bar that looks twice as tall is actually only slightly larger. The answer choices include the number you get from misreading the scale because the test writers know this mistake. Always check the units and the axis range before you compute.
Step-by-step strategy
When to use: any question with a graph, table, chart, or statistical data set.
- 1Read the title, axis labels, units, and legend. Note whether the axis starts at zero or at a non-zero value.
- 2Identify what the question asks. Is it a value, a comparison, or a percentage change?
- 3Find the specific data points the question references. Read them from the chart with the correct units.
- 4Compute, and verify the answer uses the same units the question asks for.
When not to use: when the question is a pure probability or combinatorics problem with no data set to interpret.
Worked example
A bar chart shows the number of books sold by a store each month from January to June. The y-axis is labeled in hundreds of books. The bar for March reaches 40. Step 1: Read the chart. The y-axis is in hundreds. March's bar reaches 40, so March sales are 40 hundred, or 4,000 books. Step 2: Identify what the question asks. If it asks for total March revenue at $15 per book, you need dollars. Step 3: Verify the units. The answer is in dollars, and the chart was in hundreds of books. The conversion is correct. Step 4: If the answer choices include both 600 and 60,000, the test is checking whether you read the scale. The answer is 60,000.
Related pages
Ready to put these strategies to work?
Study the savvy way with unlimited adaptive GRE-style questions, exact feedback, and full-length exams at peak difficulty. Your first full-length practice test is free.