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Question

A random variable X is distributed at random between the values 0 and 1 in such a way that the PDF of X is f(x) = x2(1 - x3), where k is a constant. The value of k is:

This question was previously asked in
SSC CGL 2023 (Tier-II) Paper 1 Previous Year Paper (26-Oct-2023) (Shift-1)
The correct answer is

6

To ensure that f(x) is a valid probability density function (PDF), we integrate f(x) over the interval [0, 1] and set the integral equal to 1. Solving this gives the value of k as 6.

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Similar Questions

  1. Let the joint probability density function of \( (X, Y) \) be

    \[f(x, y) = \begin{cases} 6xy^2 & \text{if } 0 < x < 1, 0 < y < 1 \\ 0, & \text{otherwise} \end{cases}\]

     

    Then \( P\left(\frac{1}{2} < X < \frac{3}{4}\right) \) is:

  2. Let X and Y have the joint p.m.f. f(x, y) = x + y / 21, where x = 1, 2, 3 and y = 1, 2. The marginal p.m.f. of X is:

  3. For a random variable X following Poisson distribution with parameter 5, the variance of X is:

  4. If \( n \) is a natural number, then, for what value of \( k \) is the following function a probability mass function?

    \[ f(x) = \frac{n!}{x!(n-x)!}k^{x}(1-k)^{n-x}, \quad x = 0,1,2,\ldots,n \]

  5. Let \( X \) have pdf:

    \[ f(x) = \begin{cases} \frac{3(2x - x^2)}{4} & \text{for } 0 \leq x \leq 2, \\ 0, & \text{otherwise} \end{cases} \]

    Then the mode is equal to:

  6. If the first two raw moments of X are equal to zero, then P(X = 0) is equal to:

  7. Let the probability density function of \( X \) be:

    \[ f(x) = \begin{cases} 3(1-x)^2 & \text{for } 0 \leq x \leq 1 \\ 0 & \text{otherwise} \end{cases} \]

    Then \( P\left(\frac{1}{2} < X < \frac{3}{4}\right) \) is equal to:

  8. Let the probability mass function of \( X \) be given by:

    \[ p(x) = c \frac{4^x}{x!}, \quad x = 0,1,2,3, \ldots \]

    Then the constant \( c \) is equal to:

  9. In an industry, the risk of suffering from occupational disease is 20%. The probability that out of 6 workers, four will suffer from the disease is:

  10. If X has the probability density function:

    \( f(x) = \begin{cases} \frac{1}{4}, & 1 \leq x \leq 5, \\ 0, & \text{otherwise} \end{cases} \)

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Important Questions from Probability Distribution

  1. A discrete random variable X has the following probability distribution.

    X1234567
    P(X)K2K2K3KK 22K 27K 2 + K

    What is the value of K?

  2. Which of the following are the properties of Binomial distribution?

    A. May be symmetrical or skewed

    B. Uni-modal, bell-shaped and symmetrical

    C. Asymptotic to the x-axis

    D. n and p are the two parameters

    E. μ and σ are the two parameters

    Choose thecorrectanswer from the options given below:

  3. The following two statements relate to probability distributions. Choose the correct code for the statements being correct or incorrect.

    Statement I: When ‘p' and 'q' are equal in the binomial distribution, the shape of the distribution is perfectly symmetrical irrespective of the size of 'n'.

    Statement II: The mean and the variance of Poisson distribution are not equal.

  4. Which of the following are the properties of normal distribution?

    (A) May be symmetrical or skewed

    (B) Uni-modal, bell-shaped and symmetrical

    (C) Asymptotic to the x-axis

    (D) m and p are the two parameters

    (E) μ and σ are the two parameters

    Choose the correct answer from the options given below: 

  5. Let the joint probability density function of \( (X, Y) \) be

    \[f(x, y) = \begin{cases} 6xy^2 & \text{if } 0 < x < 1, 0 < y < 1 \\ 0, & \text{otherwise} \end{cases}\]

     

    Then \( P\left(\frac{1}{2} < X < \frac{3}{4}\right) \) is:

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