EquateIt EquateIt
Book now
Year 9–10 · Year 9–10 Maths

Year 9–10 Maths — Statistics and Probability

Year 9–10 statistics extends beyond basic measures of centre to box plots, bivariate data and more complex probability. The concepts of quartiles, correlation and independent/dependent events all appear in VCE Methods and in real-world data analysis.

Key Concepts & Formulas

  • Five-number summary: minimum, lower quartile (Q1), median (Q2), upper quartile (Q3), maximum

  • IQR (interquartile range) = Q3 − Q1; measures spread of the middle 50% of data

  • Box plot (box-and-whisker): displays five-number summary; whiskers extend to min and max (or to 1.5 × IQR)

  • Outlier: a data point more than 1.5 × IQR below Q1 or above Q3

  • Scatter plot: displays two numerical variables; used to identify correlation

  • Correlation: positive (both increase together), negative (one increases as other decreases), no correlation

  • Correlation does not imply causation — two variables can be correlated without one causing the other

  • Tree diagram: shows all possible outcomes for multi-step probability experiments

  • Multiplication rule: P(A and B) = P(A) × P(B) for independent events; P(A) × P(B|A) for dependent events

  • Two-way table: organises data by two categorical variables; read probabilities directly from the table

Practice Questions

4 questions

Attempt each question before reading the hint. These are styled to match school assessment format.

Q1.A dataset: 3, 7, 8, 10, 12, 15, 18, 21, 25. Find Q1, Q2 and Q3, and draw a box plot.

4 marks

Q2.A bag has 4 red and 6 blue marbles. Two marbles are drawn without replacement. Find the probability both are red.

3 marks

Q3.A scatter plot shows a negative correlation between hours of TV watched per day and exam scores. Describe what this means and explain why it does not prove TV causes lower scores.

3 marks

Q4.200 students are surveyed: 80 play sport, 60 play music, and 30 do both. Fill in a two-way table and find the probability that a randomly chosen student plays neither sport nor music.

4 marks

Common Mistakes to Avoid

These are the errors that students most frequently make in Statistics and Probability — and that examiners are specifically watching for.

  • Confusing IQR (Q3 − Q1) with range (max − min) — they measure different aspects of spread

  • In probability trees, not multiplying along branches to find compound probabilities

  • Stating that correlation proves causation — always note that correlation only shows an association

  • Forgetting to adjust probabilities in "without replacement" problems — the denominator changes each time

Still finding Statistics and Probability difficult?

One-to-one tutoring with a specialist Year 9–10 Maths tutor is the fastest way to close gaps and build exam confidence.

Find a Year 9–10 Maths tutor Book a free assessment

Book a free assessment

Tell us the student’s year level and subject. We’ll match a tutor and set up the free diagnostic — no obligation.

  • No lock-in contracts
  • In-person across Melbourne or online statewide
  • Qualified, WWCC-checked tutors

Five quick questions, one great match.

  1. 1 Who the tutoring is for
  2. 2 Year level
  3. 3 Subjects
  4. 4 The goal
  5. 5 In-person or online
Start — takes 60 seconds

Free first assessment · No obligation · We reply within 24 hours