JAMB 2010 Mathematics · Question 17
Find the standard deviation of 2, 3, 5 and 6
Options
- A.√6
- B.√10
- C.√
- D.√
Answer: D. √
Explanation written with AI and checked against the answer key
Analyze the question: We need the standard deviation of the data set 2, 3, 5, 6. In JAMB, standard deviation is usually the population type: SD = √[Σ(x − mean)² / n]. Step 1: Find the mean Mean = (2 + 3 + 5 + 6) / 4 = 16 / 4 = 4 Step 2: Find the deviations from the mean and square them | x | x − 4 | (x − 4)² | |---|-------|----------| | 2 | −2 | 4 | | 3 | −1 | 1 | | 5 | 1 | 1 | | 6 | 2 | 4 | Σ(x − mean)² = 4 + 1 + 1 + 4 = 10 Step 3: Divide by n and take the square root Variance = 10 / 4 = 5/2 Standard deviation = √(5/2) (Note: if you used the sample formula, dividing by n − 1 = 3, you would get √(10/3), which is not among the options. So JAMB intends the division by n.) Tip: For JAMB, unless told "sample," divide by n. Remember the steps: mean → deviations → square → add → divide by n → square root. Also, option B (√10) is a trap that comes from forgetting to divide by n.AI can make mistakes. Report anything that looks wrong.
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