Statistics and Probability Review
Consolidate all statistics and probability concepts through mixed exam-style problems and revision.
Printable Worksheets
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Worksheet
Use the worksheet to complete this lesson in your book or digitally.
Q1 ยท Looking back at this unit, what is one thing about statistics or probability that surprised you or changed how you think?
Q2 ยท How might you honestly use statistics and probability in a future career or an everyday decision you will face?
Learning Intentions
Know
- All statistical displays, measures of centre and spread, bivariate analysis, and probability techniques covered in this unit.
Understand
- How to select the appropriate statistical or probability technique for a given problem or data set.
Can Do
- Solve mixed problems confidently and justify choices of display, measure and technique.
Key Terms
Misconceptions to Fix
Wrong: Theoretical probability is always more accurate than experimental probability.
Right: Theoretical probability assumes a fair/random experiment. Experimental probability may be more accurate if the theoretical assumptions are wrong (e.g., a biased coin).
Wrong: The Law of Large Numbers means that after many trials, the experimental probability will exactly equal the theoretical probability.
Right: The Law of Large Numbers says experimental probability approaches theoretical probability as the number of trials increases. It does not guarantee exact equality.
Statistics and Probability Review
Work through the content, activities and worked examples below. Test your understanding with the questions in the Questions phase.
Complete the following mixed problems:
- A data set has values: 12, 15, 18, 21, 24, 27, 30. Find the mean, median, range and IQR.
- A bag contains 3 red, 4 blue and 5 green marbles. Two marbles are drawn without replacement. Find P(both blue).
- A scatter plot shows a strong negative correlation between temperature and heating costs. Interpret this result.
Worked Example
Step-by-step-
1Step 1: Given that the student owns a laptop, restrict to the 25 laptop owners.
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2Step 2: Of these 25, 15 also own a mobile phone.
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3Step 3: P(mobile | laptop) = 15/25 = 3/5 = 0.6.
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4Step 4: Using the formula: P(mobile and laptop) = 15/50 = 0.3, P(laptop) = 25/50 = 0.5. P(mobile | laptop) = 0.3/0.5 = 0.6. โ
Revisit Your Thinking
Look back at your Think First response. What new understanding do you have now?
Earlier you were asked: What was your first thought on this topic?
Now that you've worked through the lesson, write a fuller answer. What changed in your thinking?
Multiple Choice
Select the best answer for each question.
1 mark The most appropriate display for comparing the heights of two groups is:
1 mark To show the relationship between hours studied and exam score, use:
1 mark If a data set has an outlier, the best measure of centre is:
1 mark Drawing two cards without replacement from a deck creates:
1 mark P(A|B) = P(A) when:
Short Answer
Show all working and justify your answers.
1. 4 marks The test scores of 10 students are: 45, 52, 58, 62, 65, 68, 72, 75, 80, 95.
(a) Calculate the mean and median.
(b) Calculate the range and interquartile range.
(c) Which measure of centre best represents this data set? Justify your answer.
2. 4 marks A coin is biased so that P(head) = 0.6. The coin is flipped 3 times.
(a) Draw a tree diagram.
(b) Find P(exactly 2 heads).
(c) Find P(at least 1 head).
3. 3 marks A scatter plot shows the relationship between study time and test score. Describe how you would determine whether the correlation is positive, negative or none, and explain how you would draw a line of best fit.
Marking guidance: 1 mark each for MCQs. See mark allocations for each short answer question.