Reach your peak.
A quick run every day, an explanation for every question, and full-length tests on official timing.
Full-length tests
98 questions across four modules, in the digital SAT’s order and on its timing, with a highlighter, a question map and a timer you can see.
How it works
A quick run with three hearts. String right answers together and the questions get harder and the points multiply.
Every question is tagged by domain and skill, and every answer comes with an explanation.
Practice any single skill at any difficulty, or just the questions you got wrong.
Come back tomorrow and climb. Progress shows your accuracy and your strongest skills.
Every question is tagged by section, domain, skill and difficulty, so you can practice exactly what you need. Full tests run like test day: two Reading & Writing modules, a break, then two Math modules.
9 easy, 9 medium, 9 hard and 9 challenging questions free every day, each with a full explanation. Filter by section, domain, skill and difficulty. Resets at midnight Central Time.
Take any test on official timing, extended 1.5× time, or untimed to focus purely on accuracy.
Four modules in official order. The second module of each section adapts to how you did on the first.
1,023 essential SAT words. Browse the list, flip flashcards, or quiz yourself.
Accuracy across daily practice and full tests, your strongest skills, and the ones that need the most help.
PEAK Survivor, Hole and Peak Defense: three games powered by SAT practice questions.
Explanations
Not just the right letter: how to get there, and why the tempting answer is wrong.
A store raises the price of a jacket by 20%. Later, it lowers the new price by 20%. The final price is what percent of the original price?
Check with $100: $100→then$120→then$96
Up 20% means × 1.20. Down 20% means × 0.80.
1.20 × 0.80 = 0.96
The final price is 96% of the original. That’s B.
The 20% cut is taken from the higher price, so it removes more than the 20% increase added.
Test day
Every Peakscor full test follows this order. In the standard tests, the second module of each section adapts to how you did on the first.
27 questions32 min
27 questions32 min
10 min
22 questions35 min
22 questions35 min
98 questions · 2 hr 14 min of testing, plus the break
Plans
The free plan is the real thing, not a trial. Pro removes the limits. Peak adds the full course and a plan to test day.
$0no card needed
$20a month, or $200 a year
$29a month, or $280 a year
Prices in US dollars. Cancel anytime.
FAQ
The Daily, plus 36 practice questions every day: 9 easy, 9 medium, 9 hard and 9 challenging, each with a full explanation. Full-length Test A, Challenge Test 1 and all 1,023 vocabulary words are free too, as are the 20-question diagnostic, each Learn module’s overview and first lesson, and PEAK Survivor’s first map. No card needed.
Pro is $20 a month or $200 a year: unlimited practice with no daily limit, plus every full-length test and Challenge test, and every game map and level. Peak is $29 a month or $280 a year: everything in Pro, plus the full Learn course and Peak Plan. Cancel anytime from your account.
98 questions across four modules, in the digital SAT’s order: Reading & Writing Module 1 and Module 2 (27 questions each), a 10-minute break, then Math Module 1 and Module 2 (22 questions each). On official timing that’s 2 hr 14 min of testing. You get estimated section scores and a total at the end.
Yes. In the standard full-length tests, Module 2 of each section is the harder version if you get 60% or more of Module 1 right, and the easier version if you don’t. Challenge tests use the hardest material throughout.
Official timing, extended 1.5× time, or untimed, on every test, including the free ones. Extended time allows 48 minutes for each Reading & Writing module and about 52 for each Math module. Untimed removes the clock so you can focus on accuracy.
A quick run with three hearts. Each right answer builds your streak: the questions get harder as it grows, and your points multiply (×2 from three in a row, ×3 from six). A miss costs a heart and drops you back to easy. Best is your longest streak.
Every day at midnight Central Time. You get a fresh 9 easy, 9 medium, 9 hard and 9 challenging.
No. Peakscor is an independent SAT practice tool, not affiliated with the College Board. Scores shown are estimates.
Free, no card.
Inference and margin of error · Lesson 4
A random sample speaks for the population it was randomly chosen from, and only that population. If a sample is chosen at random from the 9th graders at one school, the results describe the 9th graders at that school. They don't describe all students at the school, 9th graders at other schools, or teenagers in general.
Ask two questions. Where was the sample chosen from? That list or group is the population. Was the choice random? If people chose themselves, such as by answering an online poll or calling a radio show, or if the researcher picked whoever was convenient, the results may not represent even that group.
The SAT also tests the opposite mistake. A random sample's results do apply beyond the people actually surveyed: that is the whole point of sampling. The results apply only to the people surveyed is too narrow when the sample was random.
So when a correct choice estimates a single population value from a margin of error, it names the right population, gives the range and hedges with a word such as plausible. Other correct choices may simply name the right group, compare two groups with reasonable to conclude, point out a bias, or say what the data don't show (Lesson 5). None of them claim more than the sample supports.
To which of the following groups can the results of the survey be generalized?
Which of the following is the most appropriate conclusion?
The most tempting wrong choice often keeps the right numbers but swaps in a bigger group: all adults in the city instead of the fitness clubs' adult members, the state instead of the county. Check the group word by word.
Only the people surveyed sounds careful, but it is wrong for a random sample, which is chosen precisely so its results stand for the population it came from.
Online polls, call-in votes and whoever walked by are not random. A large number of responses doesn't fix that, and the margin of error doesn't account for it.
Desmos can't help here. Deciding which population a sample represents is a reading question with nothing to compute.
Spend the time on the passage instead: find where the sample was chosen from and whether it was chosen at random, then match that group to the choices.
Choose a section, then practice a whole domain or drill a single skill.
Each test mirrors the digital SAT: 98 questions across four modules, 2 hr 14 min on official timing.
Same 98-question format, but every question is drawn from the toughest SAT material: Challenging-tier math throughout and the hardest reading.
Study the classic SAT vocabulary list. Browse, flip flashcards, or quiz yourself.
Practice free every day. Pro removes the limits. Peak adds the full course and a plan to test day.
Prices in USD. Switch or cancel your plan at any time.
Online payment hasn’t launched, so nothing here asks for a card. Everything on the free plan stays free.
Save your progress and pick up where you left off.
Your account keeps game coins, characters and map progress in sync across devices. Practice history stays on this device.