NDA
Mathematics
Statistics
2025
NDA 2025 (Phase 1)
NDA Mathematics Question (2025) — Solution
Question
Consider the following for the four (04) items that follow: The frequency distribution of height of students of a class is given below: Height (in cm) Number of Students 160–162 12 162–164 15 164–166 24 166–168 13 The height which occurs most frequently in the class is
Options
- A. 163.5 cm
- B. 163.9 cm
- C. 164.5 cm
- D. 164.9 cm
Step-by-step solution
The height which occurs most frequently corresponds to the mode of the given frequency distribution. The maximum frequency is 24, which corresponds to the class interval 164-166. Thus, the modal class is 164-166. The lower limit of the modal class, l = 164 Frequency of the modal class, f_1 = 24 Frequency of the class preceding the modal class, f_0 = 15 Frequency of the class succeeding the modal class, f_2 = 13 Class size, h = 2 The mode is calculated using the formula: Mode = l + ( f_1 - f_0 2f_1 - f_0 - f_2 ) h Substituting the values: Mode = 164 + ( 24 - 15 2(24) - 15 - 13 ) 2 Mode = 164 + ( 9 48 - 28 ) 2 Mode = 164 + ( 9 20 ) 2 Mode = 164 + 9 10 = 164 + 0.9 = 164.9 The height which occurs most frequently is 164.9 cm. Answer: 164.9 cm
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