SPM 2019 Add Maths Paper 2, Question 5Statistics
Solved on video in English and Bahasa Melayu · 7 marks · Older syllabus, Statistics · 4:25 video
The question
Table 1 shows the deviation from the mean mark scored by Nora in a monthly test. The deviation from the mean mark for Sejarah has been left out. Table 1: Bahasa Melayu = 10, Bahasa Inggeris = 2, Mathematics = 23, Additional Mathematics = -19, Sejarah = (blank), Pendidikan Islam = -6, Physics = -22, Chemistry = -20, Biology = 2. It is given that her mean mark for all 9 subjects is 60. Find (a) the median mark, (b) the standard deviation.
[7 marks]
4:25Step 1
Since deviations from the mean must sum to zero over all 9 subjects: 10+2+23-19+x-6-22-20+2 = 0, where x is Sejarah's deviation.
Why this step
The mean is the balance point, so deviations above and below it always add up to 0. That is how we find the missing one.
6 more steps, each with the reason for it, in the full solution
Final answer
(a) median = 62; (b) standard deviation ≈ 17.695
Where students lose marks
Watch out: deviations from the mean add up to 0, so use that to find Sejarah's value. The median of 9 marks is the 5th.
Watch every step of this question solved on video (4:25), with the reason behind each step and a box that checks your own answer.
No card. Every past-year question on video, in English and BM.
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