Unit 4: Statistics and Probability
Topic 4.3: Measures of Spread and Outliers Questions
Practice 20 exam-style questions for IB Math AI SL Topic 4.3. Review the question stems below, then unlock the full Question Bank to access markschemes, model answers, and AI grading.
1find1 mark
State the population SD formula in words.
Markscheme and model answer locked
Unlock Question2find1 mark
A data set has variance 49. Find the SD.
Markscheme and model answer locked
Unlock Question3find1 mark
A data set has mean 20. If every value is multiplied by 3, find the new mean.
Markscheme and model answer locked
Unlock Question4find2 marks
A small dataset 4, 6, 8, 10, x has mean 9. Find x.
Markscheme and model answer locked
Unlock Question5find1 mark
A frequency table records the number of children per household: 0: 4, 1: 12, 2: 18, 3: 9, 4: 5, 5: 2. Find the mode.
Markscheme and model answer locked
Unlock Question6find1 mark
A data set has mean 50. If 12 is added to every value, find the new mean.
Markscheme and model answer locked
Unlock Question7find2 marks
A teacher records the number of days absent per student in one term: 0: 22, 1: 5, 2: 3, 3: 2, 4: 1, 5: 0, 6: 1. (a) Find the modal number of days absent. (b) Briefly state what the mode tells the school.
Markscheme and model answer locked
Unlock Question8find2 marks
Frequency table: [0,5): 4, [5,10): 9, [10,15): 14, [15,20): 11, [20,25): 7. Identify the modal class and the estimated modal value (midpoint).
Markscheme and model answer locked
Unlock Question9write down2 marks
The lengths (in minutes) of 42 podcast episodes are grouped as: [0,5): 7, [5,10): 19, [10,15): 11, [15,20): 5.
(a) Write down the modal class.
(b) Estimate the modal length using the midpoint of that class.
(a) Write down the modal class.
(b) Estimate the modal length using the midpoint of that class.
Markscheme and model answer locked
Unlock Question10find1 mark
True or false: the mode is the only average that can have multiple values for one dataset.
Markscheme and model answer locked
Unlock Question11find1 mark
A survey records favourite colour: red 25, blue 38, green 17, yellow 12, purple 8. Find the mode.
Markscheme and model answer locked
Unlock Question12find2 marks
A teacher multiplies every score by 1.2 (a 20% boost). If the original mean was 50, find the new mean.
Markscheme and model answer locked
Unlock Question13find2 marks
A dataset has mean 50 and SD 8. State the interval mean ± 2σ.
Markscheme and model answer locked
Unlock Question15find3 marks
The mean of 5 numbers is 18. Four of them are 12, 15, 20, 22. Find the fifth number.
Markscheme and model answer locked
Unlock Question17find2 marks
Compare the SDs of two datasets: A = {2, 4, 6, 8, 10} and B = {6, 6, 6, 6, 6}. Without calculation, which has the larger SD and why?
Markscheme and model answer locked
Unlock Question18find3 marks
A frequency table records weekly hours of study: 2 hours: 5 students; 3 hours: 8 students; 4 hours: 10 students; 5 hours: 4 students; 6 hours: 3 students. Calculate the mean hours of study.
Markscheme and model answer locked
Unlock Question19find1 mark
Find the mode of: 4, 7, 4, 9, 4, 12, 7.
Markscheme and model answer locked
Unlock Question20find2 marks
A teacher adds 5 marks to every student''s test score. If the original mean was 64, find the new mean.
Markscheme and model answer locked
Unlock QuestionReady to practice Topic 4.3?
Get instant AI feedback on your answers, view detailed markschemes, and track your progress across all IB Math AI SL topics.