CMA Foundation · Fundamentals of Business Mathematics and Statistics · Statistical Representation of Data
A bank branch records the monthly salaries (in rupees thousands) of 40 employees. The minimum is 18 and the maximum is 78. The manager wants 6 equal-width classes covering the whole range. What class width should be used?
The class width is 10, because the range is 78 minus 18, which equals 60, and dividing this by the 6 desired classes gives 10. Six classes of width 10 cover all values from 18 to 78 with no gaps.
- A8
- B10Correct
- C12
- D13
Explanation
Range = 78 − 18 = 60. Width = 60 ÷ 6 = 10. Classes 18-28, 28-38, ... 68-78 cover the range exactly. Using 8 would cover only 48, so some values would be left out.
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