UCAT Probability and Data Practice Questions
Practise probability and data reasoning for UCAT Decision Making.
Written and reviewed by Dr Akash Gandhi, NHS GP (GMC 7601216) and founder of TheUKCATPeople, teaching the UCAT since 2012. Last reviewed .
Frequently asked questions
What is the UCAT Data Logic trainer?
Data Logic is a free UCAT Decision Making trainer for probability and interpreting information questions. It covers percentages, complements, choosing the right denominator, at-least-one probability, conditional probability, expected value, and reading tables and charts. Each drill is ten questions drawn at random from a bank of 170, each with four options, and every answer shows an explanation, the common trap and why each option is right or wrong.
What are UCAT probability questions like?
Probability questions in Decision Making, which the UCAT calls probabilistic reasoning, describe a situation involving chances, percentages or outcomes and ask what is most likely or whether a claim holds. Many give four answers in the form Yes or No plus a reason, so you need both the right decision and the right justification. The maths needs no specialist knowledge: fractions, complements, simple combined events and comparing rates cover most of it.
How do I work out at least one probability in the UCAT?
Use the complement. The chance of at least one success equals 1 minus the chance of no successes at all. If each of three independent tickets has a 20% chance of winning, the chance that none wins is 0.8 × 0.8 × 0.8 = 0.512, so the chance of at least one win is about 49%. Adding 20% three times to get 60% is the classic trap, because it double counts outcomes with more than one win.
Why do denominators matter in UCAT Decision Making data questions?
Many errors come from dividing by the wrong total. A percentage of respondents is not a percentage of everyone surveyed, and a percentage of one subgroup cannot be compared directly with a percentage of another. Before calculating, ask what the whole is in the question, then check the statement uses that same whole. Data Logic has questions on denominators, response rates and conditional probability that target this trap.
What are interpreting information questions in UCAT Decision Making?
Interpreting information questions give you a passage, table, chart or graph and ask which conclusion can be drawn. Some are single-answer questions; others ask you to judge five statements Yes or No. A statement is supported only if the data proves it, so watch for claims that go beyond the figures, compare different totals or assume a trend continues. Data Logic includes table reading, chart reading, misleading comparison and insufficient information questions.
Can I use a calculator in UCAT Decision Making?
Yes. A basic on-screen calculator is available in Decision Making as well as Quantitative Reasoning, and you also get a laminated notebook and pen. It helps with probability and data questions, but opening it costs time, so do simple steps such as halving or finding 10% in your head. Use Num Lock to type numbers with the keyboard. Syllogism and strongest argument questions need little or no calculation.
How should I use the Data Logic drills?
Read the free probability guide linked on the start screen, then start a drill of ten questions, answering by click or the number keys 1 to 4. Work on paper as you would in the exam. The results show your score, your pace against the exam average of about 63 seconds per question and your accuracy by skill. Retry incorrect questions straight away; missed ones also come back for review a day later.