Statistics & Probability

Probability

Determining the likelihood of an event based on favorable vs. total possible outcomes.

Questions use dice rolls, card draws, colored-ball selections, and workplace staffing scenarios. Answer choices are fractions, decimals, or percentages; outlier options near 0 or 1 are common traps.

What the exam tests

Simple Event Likelihood

Odds of a single outcome, such as a die landing on a specific number.

Favorable vs. Total Outcome Exercises

Identify the number of favorable cases and divide by the total possible outcomes.

Fractional Representation

Express the likelihood of an event as a fraction (e.g., 1/6).

Applied Word Problems

Sort through irrelevant information in a scenario to isolate the variables needed for the probability formula.

Probability Formula Application

Key rules

  • ›Probability = Favorable Cases ÷ Total Possible Outcomes.
  • ›Result is always between 0 (impossible) and 1 (certain).

Common traps

  • !Counting an outcome as both favorable and total rather than as a subset of total.

Numerical Conversion

Key rules

  • ›Convert between fractions, decimals, and percentages to match the answer format.
  • ›Fraction → decimal: divide numerator by denominator. Decimal → percent: multiply by 100.

Data Filtering

Key rules

  • ›Ignore names, dates, and descriptive details that do not affect favorable or total counts.
  • ›Identify only the two numbers the formula needs before calculating.

Reasonableness and Outlier Identification

Key rules

  • ›A valid probability must fall between 0 and 1. Eliminate any answer outside this range.
  • ›The result should feel intuitive given the scenario (e.g., 1-in-6 chance for a fair die).

Common traps

  • !Selecting an extreme answer (very close to 0 or 1) when the scenario implies a moderate likelihood.

Theory vs. Reality

Key rules

  • ›Probability predicts what could happen in theory.
  • ›Statistics analyzes what actually happened. Do not confuse the two when answering.

Try one

A standard six-sided die is rolled once. What is the probability of rolling a three?

A.1/3
B.1/6
C.1/2
D.1/4

There is 1 favorable outcome (rolling a 3) out of 6 equally likely outcomes. Probability = 1 ÷ 6 = 1/6.

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