In a series of 2n observations, half of them equal a and remaini

Subject

Mathematics

Class

JEE Class 12

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 Multiple Choice QuestionsMultiple Choice Questions

31.

The intercept on the line y = x by the circle x2 +y2 -2x = 0 is AB. Equation of the circle on AB as a diameter is

  • x2 +y2 -x-y =0

  • x2 -y2 -x-y =0

  • x2 +y2 +x-y =0

  • x2 +y2 +x-y =0

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32.

If a ≠ 0 and the line 2bx + 3cy + 4d = 0 passes through the points of intersection of the parabolas y2+ 4ax = and  x2+ 4ay = , then

  • d2 + (2b+3c)2 = 0

  • d2 +(3d+2c2) = 0

  • d2 + (2b-3c)2 = 0

  • d2 + (2b-3c)2 = 0

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33.

The eccentricity of an ellipse, with its centre at the origin, is 1 /2 . If one of the directrices is x = 4, then the equation of the ellipse is

  • 3x2 +4y2 = 1

  • 3x2+ 4y2 = 12

  • 4x2 +3y2 = 12

  • 4x2 +3y2 = 12

311 Views

34.

Consider the following statements:
(a) Mode can be computed from histogram
(b) Median is not independent of change of scale
(c) Variance is independent of the change of origin and scale. Which of these is/are correct?

  • only (a)

  • only (b)

  • only (a) and (b)

  • only (a) and (b)

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35.

In a series of 2n observations, half of them equal a and remaining half equal –a. If the standard deviation of the observations is 2, then |a| equals 

  • 1/n

  • square root of 2
  • 2

  • 2


C.

2

In the 2n observations, half of them equal to a and remaining half equal to -a. Then the mean of total 2n observations is equal to zero.
 straight S. straight D space equals space square root of fraction numerator straight capital sigma left parenthesis straight x minus straight x right parenthesis squared over denominator straight N end fraction end root
space 2 space equals space square root of fraction numerator Σx squared over denominator 2 straight n end fraction end root
space 4 space equals space fraction numerator Σx squared over denominator 2 straight n end fraction space
rightwards double arrow space 4 space equals space fraction numerator 2 na squared over denominator 2 straight n end fraction
rightwards double arrow straight a squared space equals 4
|a| =2

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36.

The probability that A speaks truth is 4/ 5 , while this probability for B is 3/ 4 . The probability that they contradict each other when asked to speak on a fact is

  • 3/20

  • 1/20

  • 7/20

  • 7/20

141 Views

37.

Suppose four distinct positive numbers a1, a2, a3, a4 are in G.P. Let b1 = a1, b2 = b1 + a2, b3 = b2 + a3 and b4 = b3 + a4.
Statement-I: The numbers b1, b2, b3, b4are neither in A.P. nor in G.P. Statement-II: The numbers b1, b2, b3, b4 are in H.P.

  • Both statement-I and statement-II are true but statement-II is not the correct explanation of statement-I

  • Both statement-I and statement-II are true, and statement-II is correct explanation of Statement-I

  • Statement-I is true but statement-II is false.

  • Statement-I is true but statement-II is false.

233 Views

38.

If x = ω – ω2 – 2. Then the value of (x4 + 3x3 + 2x2 – 11x – 6) is

  • 0

  • -1

  • 1

  • 1

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39.

Maximum sum of coefficient in the expansion of (1 – x sinθ + x2 )n is

  • 1

  • 2n

  • 3n

  • 3n

126 Views

40.

Let R = {(1, 3), (4, 2), (2, 4), (2, 3), (3, 1)} be a relation on the set A = {1, 2, 3, 4}. The relation R is

  • a function

  • reflexive

  • not symmetric

  • not symmetric

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