Statistics · JEE Main previous year questions

2012 3 questions

1. Q92012 · 26 May 2012 · Shift 1

   Statement 1: The variance of first $n$ odd natural numbers is $\frac{n^2-1}{3}$ Statement 2: The sum of first $n$ odd natural number is $n^2$ and the sum of square of first $n$ odd natural numbers is $\frac{n(4n^2+1)}{3}$.

   1. A.Statement 1 is true, Statement 2 is false.
   2. B.Statement 1 is true, Statement 2 is true; Statement 2 is not a correct explanation for Statement 1.
   3. C.Statement 1 is false, Statement 2 is true.
   4. D.Statement 1 is true, Statement 2 is true, Statement 2 is a correct explanation for Statement 1.
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   Answer: A

2. Q82012 · 12 May 2012 · Shift 1

   If the mean of $4,7,2,8,6$ and $a$ is 7, then the mean deviation from the median of these observations is

   1. A.8
   2. B.5
   3. C.1
   4. D.3
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   Answer: D

3. Q92012 · 7 May 2012 · Shift 1

   The frequency distribution of daily working expenditure of families in a locality is as follows: Expenditure (in Rs.) ($x$) 0-50 50-100 100-150 150-200 200-250 No. of families ($f$) 24 33 37 $b$ 25 If the mode of the distribution is Rs. 140, then the value of $b$ is

   1. A.34
   2. B.31
   3. C.26
   4. D.36
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   Answer: D