AP Statistics · Reference

AP Statistics formula sheet: every formula for the 2027 exam.

Q: Should I still study the geometric distribution for AP Statistics?

No. College Board removed it from the course effective Fall 2026, so it cannot be examined in May 2027. Be careful with older material: most textbooks printed before the revision still teach it, and a lot of third-party practice still includes geometric questions.

Q: Can I bring my own copy of the AP Statistics formula sheet?

No. The reference information is handed to you at the exam and proctors collect it at the end. You may write anywhere in the blank space in the booklet during the exam, so it doubles as scratch paper.

Q: Is the AP Statistics formula sheet the same as the one in my textbook?

Usually not. Textbook reference pages carry more than College Board prints, and since the Fall 2026 revision some of them list formulas that have been taken off the official sheet.

Q: Will my practice materials match the 2027 formula sheet?

Released exams and most third-party practice were built against the previous sheet, so treat their reference pages as out of date. The formulas themselves are unchanged where they survive; it is the list that shrank.

Q: What is the difference between the formula sheet and a cheat sheet?

The formula sheet is the official reference you are handed. A cheat sheet adds the key idea and the common mistake for each unit, which is the part the official sheet deliberately leaves out.

College Board hands you the formulas and the z, t and chi-square tables on exam day, so the AP Stats exam tests whether you can pick the right procedure, not whether you memorized it. The AP Statistics formula sheet, also called the AP Statistics equation sheet, changed for the 2027 exam: 4 formulas students still revise are no longer on it.

Updated September 2026Part of AP Statistics Review

By Mahmudul Hasan

Is the formula sheet provided on the AP Statistics exam?

Yes. The formulas and the statistical tables are provided for both the multiple-choice and free-response sections, and you are not expected to memorize them. What the sheet cannot do is tell you which procedure a question wants, or which condition to check before you use it, and that is where the marks actually move.

Students call it the AP Stats formula sheet. College Board’s own title is AP Statistics Exam Reference Information, and it arrives as an 11-page booklet rather than a one-page AP Statistics reference sheet. The formulas run to 2 pages and the tables fill the rest. You can find it as the Appendix to the AP Statistics Course and Exam Description (PDF); no standalone 2027 booklet has been published yet.

On calculators, College Board is more specific than most summaries suggest. A graphing calculator with statistical capabilities is expected for both sections, not merely permitted. Bluebook supplies a built-in Desmos graphing calculator alongside whatever handheld you bring. A nongraphing calculator is not acceptable even if it can do the statistics. You do not need to clear your calculator’s memory.

The sections below are grouped the way the sheet itself is.

What changed on the formula sheet for 2027

AP Statistics was revised effective Fall 2026, so students sitting the exam in May 2027 are the first cohort on the new course. College Board’s AP Statistics revisions removed 5 topics and consolidated 9 units into 5. Three of those removals took formulas off the sheet with them.

Formulas that are no longer on the sheet

Correlation: r

Still taught, no longer given. Read it off your calculator output.

Slope: b = r · (s_y / s_x)

Gone with the rest of the regression-inference block.

Geometric: P(X = x) = (1−p)^x−1p

The geometric distribution was removed from the course entirely, not just from the sheet.

Standard error of the slope: s_b

Unit 9, inference for slopes, no longer exists.

The chi-square statistic stayed, but the goodness-of-fit test did not. The course now covers 2 chi-square tests, both on two-way tables: the test for independence and the test for homogeneity.

How the exam itself changed

	Through May 2026	From May 2027
Units	9	5
Multiple choice	40 questions, 5 choices each	42 questions, 4 choices each
Free response	6 questions, 4 points each	4 questions, 10 points each
Investigative Task	Yes, worth 25%	Removed
Delivery	Hybrid digital, paper response booklet	Fully digital in Bluebook
Reference information	Printed booklet	Printed booklet, unchanged

Section weights did not move: multiple choice and free response are still worth 50% each across 3 hours. If you are working through practice sets, note that the AP Statistics FRQ section is now 4 questions scored out of 10 rather than 6 scored out of 4.

The AP Statistics formula sheet, by section

The sheet runs to 3 sections. Nearly every inference formula in the third is one of the same 2 shapes: statistic ± critical value × standard error for an interval, and (statistic − parameter) ÷ standard error for a test statistic. Recognising that turns a long list into 2 ideas.

I. Descriptive statistics

Sample mean: x̄ = (Σx_i) / n

The average of the data.

Standard deviation: s = √[ Σ(x_i − x̄)² / (n − 1) ]

Typical distance of values from the mean.

Regression line: ŷ = a + bx

The predicted response from the least-squares line. This is now the only regression formula on the sheet.

II. Probability and distributions

Addition rule: P(A ∪ B) = P(A) + P(B) − P(A ∩ B)

Probability that A or B happens.

Conditional probability: P(A | B) = P(A ∩ B) / P(B)

Probability of A given B.

Expected value: μ_X = Σ x_i · P(x_i)

The mean of a discrete random variable.

Standard deviation of X: σ_X = √[ Σ(x_i − μ_X)² · P(x_i) ]

Spread of a discrete random variable. Easy to miss, and it sits right beside the mean.

Binomial: P(X = x) = _nC_x p^x(1−p)^n−x

With μ_X = np and σ_X = √(np(1−p)).

III. Sampling distributions and inference

This is the section most pages stop half-way through. It has 2 general forms, then a table for categorical data (proportions) and a table for quantitative data (means). College Board now separates standard deviation, which uses the population parameter, from standard error, which estimates it from your sample. That split is new, and the notation moved from s to SE with it.

Standardized test statistic: (statistic − parameter) / standard error

Produces the test statistic you convert into a p-value and weigh against the null hypothesis.

Confidence interval: statistic ± (critical value)(standard error)

The second half is the margin of error.

Chi-square: χ² = Σ (observed count − expected count)² / expected count

For the tests of independence and homogeneity.

Proportions, one and two samples

One proportion: μ_p̂ = p, σ_p̂ = √[ p(1−p) / n ]

Standard deviation, using the population proportion.

SE_p̂ = √[ p̂(1−p̂) / n ]

Standard error, estimated from the sample.

Two proportions: SE_p̂1−p̂2 = √[ p̂₁(1−p̂₁)/n₁ + p̂₂(1−p̂₂)/n₂ ]

For a difference of 2 proportions.

Pooled: p̂_c = (n₁p̂₁ + n₂p̂₂) / (n₁ + n₂)

Used when the test assumes p₁ = p₂. College Board changed this form; older sheets wrote it with counts.

Means, one and two samples

One mean: μ_x̄ = μ, σ_x̄ = σ / √n

Standard deviation of the sampling distribution.

SE_x̄ = s / √n

Standard error, the version you almost always use.

Two means: SE_x̄1−x̄2 = √[ s₁²/n₁ + s₂²/n₂ ]

For a difference of 2 means. Paired data uses the one-sample form on the differences.

The statistical tables (z, t, and chi-square)

The 3 tables do the same job from opposite ends: the z table turns a score into a probability, while the t and chi-square tables turn a probability into a cut-off.

Table A: standard normal (z)

Cumulative probability P(Z < z), the area below z. Used with proportions and large samples.

Table B: t-distribution

Critical values t* by degrees of freedom. Used for inference about means.

Table C: chi-square

Critical values by degrees of freedom, for the tests of independence and homogeneity on two-way tables.

What the formula sheet does not give you

The sheet is deliberately thin. Everything below is examinable and none of it is printed, which is why knowing the sheet is not the same as being ready for the exam.

The conditions

Not one condition appears on the sheet, and conditions carry their own marks. College Board names 3 for inference about proportions and means: the randomization condition, the data should come from a random sample; the 10% condition, when sampling without replacement the population should be at least 10 times the sample size; and the normality condition, successes and failures at least 10. Chi-square swaps the third for the expected values condition, all expected counts at least 5.

Note the threshold split, because it is a common slip: 10 for normality, 5 for expected counts. The normality condition is the check most textbooks call the large counts condition ap stats classes learn as np ≥ 10 and n(1−p) ≥ 10. A test uses the expected counts np₀ and n(1−p₀); an interval uses the observed p̂.

Formulas you still need from memory

The z-score, z = (x − μ) / σ

Not on the sheet. Section I gives only the mean, standard deviation and regression line.

IQR and the outlier fences

Q3 − Q1, and the 1.5 × IQR rule. Absent.

Residuals, observed − predicted

Absent, and residual plots are still examined.

r and r²

Both removed from the sheet for 2027. Your calculator reports them; you interpret them.

Also missing, and harder to look up under time pressure: which procedure a question calls for, how to word an interpretation of a confidence interval or a p-value, and your calculator’s menu paths.

How to use the formula sheet

Name the procedure before you reach for a formula. Deciding you need a two-sample t-interval, then finding its standard error, is reliable; scanning the sheet for something that fits the numbers in front of you is not, because several formulas will look plausible.

Then check the condition the sheet does not print, run the arithmetic on the calculator, and write the conclusion in context. Practice with the real booklet open so its layout is familiar before test day.

For a concept-first version that pairs each unit with its key idea and the mistake to avoid, use our AP Statistics cheat sheet. The AP Statistics exam score calculator turns a practice raw score into a 1–5.

Frequently asked questions

Quick answers, checked against College Board.

Should I still study the geometric distribution for AP Statistics?

No. College Board removed it from the course effective Fall 2026, so it cannot be examined in May 2027. Be careful with older material: most textbooks printed before the revision still teach it, and a lot of third-party practice still includes geometric questions.

Can I bring my own copy of the AP Statistics formula sheet?

No. The reference information is handed to you at the exam and proctors collect it at the end. You may write anywhere in the blank space in the booklet during the exam, so it doubles as scratch paper.

Is the AP Statistics formula sheet the same as the one in my textbook?

Usually not. Textbook reference pages carry more than College Board prints, and since the Fall 2026 revision some of them list formulas that have been taken off the official sheet.

Will my practice materials match the 2027 formula sheet?

Released exams and most third-party practice were built against the previous sheet, so treat their reference pages as out of date. The formulas themselves are unchanged where they survive; it is the list that shrank.

What is the difference between the formula sheet and a cheat sheet?

The formula sheet is the official reference you are handed. A cheat sheet adds the key idea and the common mistake for each unit, which is the part the official sheet deliberately leaves out.

More AP Statistics guides

Up to pillar

AP Statistics Review

Back to the full exam guide.

Sister

AP Statistics Cheat Sheet

A unit-by-unit cram chart.

Cross-pillar

AP Statistics FRQ

How the free response is scored.