WAEC 2014 Mathematics · Question 43
c c height 2 3 4 5 6 frequency 2 4 5 3 1 The table shows the distribution of the height of plants in a…
Question
The table shows the distribution of the height of plants in a nursery. Calculate the mean height of the plants.
- A.3.8
- B.3.0
- C.2.8
- D.2.3
Answer: A. 3.8
Explanation written with AI and checked against the answer key
Analyze the question: We need the mean of a frequency distribution. Each height is weighted by how many plants have that height.
Concept: Mean = Σfx ÷ Σf
Solution:
| Height (x) | Frequency (f) | fx | |---|---|---| | 2 | 2 | 4 | | 3 | 4 | 12 | | 4 | 5 | 20 | | 5 | 3 | 15 | | 6 | 1 | 6 |
- Σf = 2 + 4 + 5 + 3 + 1 = 15
- Σfx = 4 + 12 + 20 + 15 + 6 = 57
Mean = 57 ÷ 15 = 3.8
Answer: The mean height is 3.8, which is option A.
Tip: Always build an fx column and add it up carefully. A quick check is that the mean must lie between the smallest and largest values (2 and 6). Since most of the frequency sits around 3 and 4, an answer near 3.8 is sensible.
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