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SAT One-Variable Data Questions

Mean, median, range and spread, and how outliers move them.

In short

  • One-Variable Data is part of Problem-Solving and Data Analysis, about 15% of the scored Math questions: 5 to 7 on every test.
  • Math questions from all four areas are mixed in each module and arranged from easiest to hardest.
  • Update mean with new value is the trap Rivie's practice tests set most often in One-Variable Data questions.

Common traps

Most common first, from Rivie's ten practice tests.

Update mean with new value

Find the new mean after a value is added/removed; the wrong choice averages the old mean with the new value (instead of recomputing the sum).

The usual mistake: You take (old_mean + new_value) / 2, which only works if there was exactly one prior value.

Median vs. mean

Mean is the arithmetic average; median is the middle value when sorted. With outliers, mean shifts toward the outlier and median doesn't: the right choice depends on which the question asks for.

The usual mistake: You compute one (usually mean: it's the default) and pick that, missing that the question asked for the other. Re-read the prompt before submitting.

Try a question

From Rivie's practice tests. Pick an answer to see why it is right or wrong.

The mean of four numbers is 21. If a fifth number x is added and the new mean is 23, what is x?

Practice more One-Variable Data questions free

Video lessons

Free on YouTube, picked for this topic.

Frequency Charts: learn how to work with long data sets, dot plots, and histogramsMean, median, and range from dot plots and histogramsSettele Tutoring · 13 minStandard Deviation: comparing two data sets on the SATCompares standard deviation without calculating itSettele Tutoring · 5 minDigital SAT Math - Desmos Lesson #13 Mean & MedianDesmos for mean, median, and missing valuesTutorllini Test Prep · 9 min

Frequently asked questions

Still stuck? Write to help@rivie.org. Prices are on the pricing page.

How many One-Variable Data questions are on the SAT?

College Board does not publish a count for each topic. One-Variable Data is one of 7 topics in Problem-Solving and Data Analysis, which makes up about 15% of the scored Math questions, 5 to 7 per test. That works out to about one One-Variable Data questions on a typical test.

What is the most common mistake on SAT One-Variable Data questions?

In Rivie's ten practice tests, the trap set most often in One-Variable Data questions is update mean with new value. You take (old_mean + new_value) / 2, which only works if there was exactly one prior value.

How can I practice One-Variable Data for the SAT?

Rivie's question bank sorts practice questions by topic and difficulty, so you can work on One-Variable Data on its own, and your study plan brings back the questions you miss. The free plan includes a full-length practice test and 100 practice questions a week.

More Math topics

All SAT topics

Problem-Solving and Data Analysis

Ratios, Rates, and Units

Problem-Solving and Data Analysis

Percentages

Problem-Solving and Data Analysis

Two-Variable Data and Scatterplots

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