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DSE M1 Normal Distribution Practice

DSE M1 · 60 practice questions with instant marking and worked solutions.

Normal Distribution is an important part of the DSE M1 mathematics curriculum. This topic develops standardising, normal tables, symmetry and finding the mean or standard deviation from a probability. Begin by identifying what every number, symbol, diagram and unit represents. Translate the information into a mathematical relationship before calculating. Each line of working should have a purpose. Finally use estimation, substitution, an inverse operation, or a second representation to check the result. This habit separates a misunderstanding from a copying error and makes correction more useful.

A reliable approach to Normal Distribution has four stages. First, mark the given information and the quantity required. Second, choose an appropriate representation, property or formula. Third, carry out the operations in a clear order while retaining signs and units. Fourth, return to the original context and decide whether the result is possible. For a graph or table, read the title, scale and labels before using a value. For algebra, inspect brackets, negative signs and the order of operations before simplifying.

The 60 original questions in this topic use a shared mathematical specification in Chinese and English. Difficulty rises from level 1 to level 5. Early questions establish the language and direct skills of Normal Distribution; middle questions add two-step reasoning, conversions and common variations; later questions connect ideas and require a deliberate check. In multiple-choice work, calculate before looking at the choices. In fill-in and short-answer work, retain decisive steps. For true-or-false statements, support the decision with a calculation or counterexample. 12 of them are DSE Extended Part style structured questions answered in parts (a), (b), (c), where later parts build on earlier ones.

Effective revision is more than recording a score. After completing the Normal Distribution set, group errors by concept tags and decide whether each problem arose from interpretation, forming an expression, calculation, or presenting the answer. Retry the item on a later day without opening the solution, then test the same method with a different value. If the same tag appears repeatedly, return to the explanation and rebuild the concept. If signs or units are the issue, use a fixed pre-submission checklist.

Normal Distribution is closely linked with the rest of the Extended Part: algebraic and trigonometric skills underpin calculus, and calculus in turn supports probability distributions and statistical inference. A learner who can explain aloud why every step is valid has moved beyond imitation. Estimate a reasonable range, complete an exact solution, and compare the two. Agreement between context, estimate and exact answer is strong evidence that the solution is sound.

This batch adds 20 questions, bringing the topic to 60. The new questions cover controlled variations of different concepts, with paired bilingual conditions, hints, worked solutions and reproducible checks.

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  1. 1 Basic
    $X\sim N(50,12^2)$ and $P(Z<\frac{1}{2})=0.6915$. Find $P(X>56)$. Choose the correct answer.
  2. 2 Basic
    $X\sim N(120,8^2)$ and a value $x$ has standard score $2$. Find the value of $x$. Give the answer only.

  3. 3 Basic
    $X\sim N(50,\sigma^2)$ and $P(X>66)=0.0228$. It is given that $P(Z<2)=0.9772$. Find the value of $\sigma$. Show the essential working and give the answer.

  4. 4 Basic
    $X\sim N(50,5^2)$ and $P(Z<\frac{3}{2})=0.9332$. $P(X>\frac{115}{2})$ is 0.9332. Is this true?
  5. 5 Basic
    $X\sim N(50,8^2)$ and $P(Z<\frac{1}{2})=0.6915$. Find $P(46
  6. 6 Basic
    $X\sim N(40,20^2)$ and a value $x$ has standard score $\frac{3}{2}$. Find the value of $x$. Give the answer only.

  7. 7 Basic
    $X\sim N(\mu,10^2)$ and $P(X<120)=0.9772$. It is given that $P(Z<2)=0.9772$. Find the value of $\mu$. Show the essential working and give the answer.

  8. 8 Basic
    $X\sim N(50,15^2)$ and $P(Z<\frac{3}{2})=0.9332$. $P(X>\frac{145}{2})$ is 0.9332. Is this true?
  9. 9 Basic
    $X\sim N(100,15^2)$ and $P(Z<\frac{1}{2})=0.6915$. Find $P(\frac{185}{2}
  10. 10 Basic
    $X\sim N(40,6^2)$ and a value $x$ has standard score $-\frac{3}{2}$. Find the value of $x$. Give the answer only.

  11. 11 Basic
    $X\sim N(\mu,5^2)$ and $P(X<\frac{205}{2})=0.6915$. It is given that $P(Z<\frac{1}{2})=0.6915$. Find the value of $\mu$. Show the essential working and give the answer.

  12. 12 Basic
    $X\sim N(100,5^2)$ and $P(Z<1)=0.8413$. $P(95
  13. 13 Standard
    $X\sim N(65,6^2)$ and a value $x$ has standard score $-1$. Find the value of $x$. Choose the correct answer.
  14. 14 Standard
    $X\sim N(\mu,4^2)$ and $P(X<54)=0.8413$. It is given that $P(Z<1)=0.8413$. Find the value of $\mu$. Give the answer only.

  15. 15 Standard
    $X\sim N(160,15^2)$ and $P(Z<\frac{3}{2})=0.9332$. Find $P(X>\frac{365}{2})$. Show the essential working and give the answer.

  16. 16 Standard DSE long question
    $X\sim N(100,10^2)$ and $P(Z<2)=0.9772$. Answer each part; give the answer only.
    1. (a) Find the standard score of $x=120$.
    2. (b) Find $P(X>120)$.
    3. (c) Find $P(80
  17. 17 Standard
    $X\sim N(80,6^2)$ and a value $x$ has standard score $2$. Find the value of $x$. Choose the correct answer.
  18. 18 Standard
    $X\sim N(60,\sigma^2)$ and $P(X>66)=0.0668$. It is given that $P(Z<\frac{3}{2})=0.9332$. Find the value of $\sigma$. Give the answer only.

  19. 19 Standard
    $X\sim N(100,12^2)$ and $P(Z<\frac{1}{2})=0.6915$. Find $P(94

  20. 20 Standard DSE long question
    $X\sim N(100,15^2)$ and $P(Z<1)=0.8413$. Answer each part; give the answer only.
    1. (a) Find the standard score of $x=115$.
    2. (b) Find $P(X>115)$.
    3. (c) Find $P(85
  21. 21 Standard
    $X\sim N(50,20^2)$ and a value $x$ has standard score $2$. Find the value of $x$. Choose the correct answer.
  22. 22 Standard
    $X\sim N(160,\sigma^2)$ and $P(X>168)=0.0228$. It is given that $P(Z<2)=0.9772$. Find the value of $\sigma$. Give the answer only.

  23. 23 Standard
    $X\sim N(160,15^2)$ and $P(Z<2)=0.9772$. Find $P(X>190)$. Show the essential working and give the answer.

  24. 24 Standard DSE long question
    $X\sim N(100,5^2)$ and $P(Z<1)=0.8413$. Answer each part; give the answer only.
    1. (a) Find the standard score of $x=105$.
    2. (b) Find $P(X>105)$.
    3. (c) Find $P(95
  25. 25 Advanced
    $X\sim N(50,8^2)$ and a value $x$ has standard score $\frac{3}{2}$. Find the value of $x$. Choose the correct answer.
  26. 26 Advanced
    $X\sim N(\mu,5^2)$ and $P(X<82)=0.9772$. It is given that $P(Z<2)=0.9772$. Find the value of $\mu$. Give the answer only.

  27. 27 Advanced
    $X\sim N(100,12^2)$ and $P(Z<1)=0.8413$. $P(X>112)$ is 0.1587. Is this true?
  28. 28 Advanced DSE long question
    $X\sim N(60,15^2)$ and $P(Z<2)=0.9772$. Answer each part; give the answer only.
    1. (a) Find the standard score of $x=90$.
    2. (b) Find $P(X>90)$.
    3. (c) Find $P(30
  29. 29 Advanced
    $X\sim N(120,8^2)$ and a value $x$ has standard score $-1$. Find the value of $x$. Choose the correct answer.
  30. 30 Advanced
    $X\sim N(\mu,5^2)$ and $P(X<110)=0.9772$. It is given that $P(Z<2)=0.9772$. Find the value of $\mu$. Give the answer only.

  31. 31 Advanced
    $X\sim N(70,15^2)$ and $P(Z<\frac{1}{2})=0.6915$. $P(X>\frac{155}{2})$ is 0.3085. Is this true?
  32. 32 Advanced DSE long question
    $X\sim N(60,15^2)$ and $P(Z<1)=0.8413$. Answer each part; give the answer only.
    1. (a) Find the standard score of $x=75$.
    2. (b) Find $P(X>75)$.
    3. (c) Find $P(45
  33. 33 Advanced
    $X\sim N(80,8^2)$ and a value $x$ has standard score $\frac{1}{2}$. Find the value of $x$. Choose the correct answer.
  34. 34 Advanced
    $X\sim N(100,\sigma^2)$ and $P(X>115)=0.0668$. It is given that $P(Z<\frac{3}{2})=0.9332$. Find the value of $\sigma$. Give the answer only.

  35. 35 Advanced
    $X\sim N(70,8^2)$ and $P(Z<2)=0.9772$. $P(54
  36. 36 Advanced DSE long question
    $X\sim N(100,10^2)$ and $P(Z<1)=0.8413$. Answer each part; give the answer only.
    1. (a) Find the standard score of $x=110$.
    2. (b) Find $P(X>110)$.
    3. (c) Find $P(90
  37. 37 Challenging
    $X\sim N(40,6^2)$ and a value $x$ has standard score $-2$. Find the value of $x$. Choose the correct answer.
  38. 38 Challenging
    $X\sim N(\mu,4^2)$ and $P(X<74)=0.6915$. It is given that $P(Z<\frac{1}{2})=0.6915$. Find the value of $\mu$. Show the essential working and give the answer.

  39. 39 Challenging
    $X\sim N(100,10^2)$ and $P(Z<\frac{3}{2})=0.9332$. $P(85
  40. 40 Challenging DSE long question
    $X\sim N(100,5^2)$ and $P(Z<2)=0.9772$. Answer each part; give the answer only.
    1. (a) Find the standard score of $x=110$.
    2. (b) Find $P(X>110)$.
    3. (c) Find $P(90
  41. 41 Challenging
    $X\sim N(120,10^2)$ and a value $x$ has standard score $\frac{3}{2}$. Find the value of $x$. Choose the correct answer.
  42. 42 Challenging
    $X\sim N(100,\sigma^2)$ and $P(X>106)=0.3085$. It is given that $P(Z<\frac{1}{2})=0.6915$. Find the value of $\sigma$. Show the essential working and give the answer.

  43. 43 Challenging
    $X\sim N(160,5^2)$ and $P(Z<\frac{1}{2})=0.6915$. $P(\frac{315}{2}
  44. 44 Challenging DSE long question
    $X\sim N(70,10^2)$ and $P(Z<1)=0.8413$. Answer each part; give the answer only.
    1. (a) Find the standard score of $x=80$.
    2. (b) Find $P(X>80)$.
    3. (c) Find $P(60
  45. 45 Challenging
    $X\sim N(65,8^2)$ and a value $x$ has standard score $2$. Find the value of $x$. Choose the correct answer.
  46. 46 Challenging
    $X\sim N(\mu,4^2)$ and $P(X<52)=0.6915$. It is given that $P(Z<\frac{1}{2})=0.6915$. Find the value of $\mu$. Show the essential working and give the answer.

  47. 47 Challenging
    $X\sim N(70,12^2)$ and $P(Z<\frac{3}{2})=0.9332$. $P(52
  48. 48 Challenging DSE long question
    $X\sim N(70,15^2)$ and $P(Z<2)=0.9772$. Answer each part; give the answer only.
    1. (a) Find the standard score of $x=100$.
    2. (b) Find $P(X>100)$.
    3. (c) Find $P(40
  49. 49 Elite
    $X\sim N(50,4^2)$ and a value $x$ has standard score $-1$. Find the value of $x$. Give the answer only.

  50. 50 Elite
    $X\sim N(\mu,4^2)$ and $P(X<162)=0.6915$. It is given that $P(Z<\frac{1}{2})=0.6915$. Find the value of $\mu$. Show the essential working and give the answer.

  51. 51 Elite
    $X\sim N(50,15^2)$ and $P(Z<\frac{1}{2})=0.6915$. $P(X>\frac{115}{2})$ is 0.3085. Is this true?
  52. 52 Elite DSE long question
    $X\sim N(60,10^2)$ and $P(Z<2)=0.9772$. Answer each part; give the answer only.
    1. (a) Find the standard score of $x=80$.
    2. (b) Find $P(X>80)$.
    3. (c) Find $P(40
  53. 53 Elite
    $X\sim N(80,8^2)$ and a value $x$ has standard score $-2$. Find the value of $x$. Give the answer only.

  54. 54 Elite
    $X\sim N(72,\sigma^2)$ and $P(X>88)=0.0228$. It is given that $P(Z<2)=0.9772$. Find the value of $\sigma$. Show the essential working and give the answer.

  55. 55 Elite
    $X\sim N(100,8^2)$ and $P(Z<2)=0.9772$. $P(84
  56. 56 Elite DSE long question
    $X\sim N(100,15^2)$ and $P(Z<2)=0.9772$. Answer each part; give the answer only.
    1. (a) Find the standard score of $x=130$.
    2. (b) Find $P(X>130)$.
    3. (c) Find $P(70
  57. 57 Elite
    $X\sim N(40,10^2)$ and a value $x$ has standard score $-1$. Find the value of $x$. Give the answer only.

  58. 58 Elite
    $X\sim N(\mu,12^2)$ and $P(X<184)=0.9772$. It is given that $P(Z<2)=0.9772$. Find the value of $\mu$. Show the essential working and give the answer.

  59. 59 Elite
    $X\sim N(100,15^2)$ and $P(Z<2)=0.9772$. $P(X>130)$ is 0.0228. Is this true?
  60. 60 Elite DSE long question
    $X\sim N(70,15^2)$ and $P(Z<1)=0.8413$. Answer each part; give the answer only.
    1. (a) Find the standard score of $x=85$.
    2. (b) Find $P(X>85)$.
    3. (c) Find $P(55

The report lists what you got wrong and why. Only you can see it.

Common mistakes

Common mistakes in Normal Distribution

This topic needs particular care with standardising, normal tables, symmetry and finding the mean or standard deviation from a probability. The first mistake is applying a remembered rule before reading all conditions. The second is compressing working so much that a sign, bracket, decimal point or unit disappears. The third is accepting an impossible answer without checking: for example, a probability above one, a negative physical length, an angle outside the geometric constraints, or a result far from the estimate. Separate the conditions, model, calculation and check, and finish by stating what the answer represents.

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DSE M1 mixed revision → My mistakes →

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