SAT One-variable Data and Statistics

One-variable statistics covers mean, median, range and standard deviation, and how each responds to a change in the data. Adding a value changes the mean by its effect on the total divided by the new count — comparing it to the old mean is the error here.

Practise this skill freeHow the SAT is structured
MathProblem-Solving and Data Analysis60 questions
The trap on this skill

Comparing the added value to the old mean without dividing the change across all values.

How this skill behaves

What 60 questions on it look like

90% of these questions can appear in the harder second module. On a section-adaptive test that matters: this is a skill that keeps mattering after a strong first module, not one you leave behind.

43% of the bank for this skill is rated hard, so it rewards practice past the point where the basic form feels comfortable.

medium47%
hard43%
easy10%

Difficulty mix across the 60 questions in this skill.

From the bank

Three real one-variable data and statistics questions

Each one explains the credited answer and why every other option fails.

Problem-Solving and Data Analysis · medium

The planetarium trial shelf folding setup note records five measurements for podcast transcripts from the outdoor set: 5, 7, 8, 10, 10. The mean is 8. If a sixth measurement, 14, is added to the data set, by how much does the mean increase?

  1. A6
  2. B2
  3. C0
  4. D1correct
Why D is correct — and why the others are not

The original sum is 40. After adding 14, the new sum is 54 for 6 values, so the new mean is 9. The increase is 1. This matches the evidence or condition involving One-variable data and statistics. A final check is using the equation form named in the stem.

A. This value results from comparing the added value to the old mean without dividing the change across all values

B. This value results from comparing the added value to the old mean without dividing the change across all values

C. This value results from comparing the added value to the old mean without dividing the change across all values

Problem-Solving and Data Analysis · hard

The trailhead morning gate checkout time card records five measurements for community workshops from the weekend group: 16, 18, 19, 21, 21. The mean is 19. If a sixth measurement, 37, is added to the data set, by how much does the mean increase?

  1. A18
  2. B3correct
  3. C4
  4. D2
Why B is correct — and why the others are not

The original sum is 95. After adding 37, the new sum is 132 for 6 values, so the new mean is 22. The increase is 3. The key support is the way the item treats One-variable data and statistics. A final check is checking the inequality direction after each operation.

A. This value results from comparing the added value to the old mean without dividing the change across all values

C. This value results from comparing the added value to the old mean without dividing the change across all values

D. This value results from comparing the added value to the old mean without dividing the change across all values

Problem-Solving and Data Analysis · easy

The foundry front frame staging receipt records five measurements for documentary interviews from the indoor set: 14, 16, 17, 19, 19. The mean is 17. If a sixth measurement, 41, is added to the data set, by how much does the mean increase?

  1. A24
  2. B5
  3. C4correct
  4. D3
Why C is correct — and why the others are not

The original sum is 85. After adding 41, the new sum is 126 for 6 values, so the new mean is 21. The increase is 4. That reasoning is tied to the item-specific detail about One-variable data and statistics. A final check is using the vertex, intercept, or factor that the stem makes relevant.

A. This value results from comparing the added value to the old mean without dividing the change across all values

B. This value results from comparing the added value to the old mean without dividing the change across all values

D. This value results from comparing the added value to the old mean without dividing the change across all values

60 questions on this skill, free to start.

Ten a day at no cost, each with the same explanation. One account covers SAT, ACT and AP.

Start free
FAQ

One-variable Data and Statistics questions

How does an outlier affect mean and median?

It pulls the mean toward itself and usually leaves the median almost unchanged, which is why the median is preferred for skewed data.

Do I need to calculate standard deviation?

No. The SAT asks you to compare spreads qualitatively — which data set is more spread out — not to compute it.
Last reviewed 2026-08-28. Format and scoring facts sourced to College Board. Question counts describe the PrepScore bank, not the exam.
Same domain
Ratios, Rates, and Proportions60 questionsTwo-variable Data and Scatterplots56 questionsProbability and Conditional Probability45 questionsInference, Margin, and Model Claims45 questions

Practise one-variable data and statistics until the trap stops working.

Real Digital SAT questions, the reasoning on every option, and a mistake bank that only clears when you get it right.

Start freeSAT guide