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MathematicsList match+4 / -1Question 14 of 48

JEE Advanced 2025 · Paper 1, Mathematics question 14

Consider the following frequency distribution:

Value 4 5 8 9 6 12 11
Frequency 5 f1f_1 f2f_2 2 1 1 3

Suppose that the sum of the frequencies is 19 and the median of this frequency distribution is 6.

For the given frequency distribution, let α\alpha denote the mean deviation about the mean, β\beta denote the mean deviation about the median, and σ2\sigma^2 denote the variance.

Match each entry in List-I to the correct entry in List-II and choose the correct option.

List-I

  • P
    7f1+9f27f_1 + 9f_2 is equal to
  • Q
    19α19\alpha is equal to
  • R
    19β19\beta is equal to
  • S
    19σ219\sigma^2 is equal to

List-II

  • 1
    146146
  • 2
    4747
  • 3
    4848
  • 4
    145145
  • 5
    5555
Choose one option
Answer and worked solution

Official answer: C

Frequencies. 5+f1+f2+2+1+1+3=195+f_1+f_2+2+1+1+3=19, so f1+f2=7f_1+f_2=7.

Median. In order the values are 4 (×5), 5 (×f1f_1), 6 (×1), 8 (×f2f_2), 9, 11, 12. The median is the 10th value. For it to be 6 we need 5+f1<10≤6+f15+f_1<10\le6+f_1, so f1=4f_1=4 and f2=3f_2=3.

(P) 7⋅4+9⋅3=557\cdot4+9\cdot3=55 → (5).

Mean. 20+20+6+24+18+33+1219=13319=7\frac{20+20+6+24+18+33+12}{19}=\frac{133}{19}=7.

(Q)
19α=∑f∣x−7∣=5⋅3+4⋅2+1+3⋅1+2⋅2+3⋅4+5=48  →  (3).19\alpha=\sum f|x-7|=5\cdot3+4\cdot2+1+3\cdot1+2\cdot2+3\cdot4+5=48 \;\to\; (3).

(R)
19β=∑f∣x−6∣=5⋅2+4⋅1+0+3⋅2+2⋅3+3⋅5+6=47  →  (2).19\beta=\sum f|x-6|=5\cdot2+4\cdot1+0+3\cdot2+2\cdot3+3\cdot5+6=47 \;\to\; (2).

(S)
19σ2=∑f(x−7)2=45+16+1+3+8+48+25=146  →  (1).19\sigma^2=\sum f(x-7)^2=45+16+1+3+8+48+25=146 \;\to\; (1).

The match is P→5, Q→3, R→2, S→1, which is option (C).