Let X be a RV with PMF Px(x) = x²/c |0 x = −3, −2, −1, 0, 1, 2, 3, otherwise. (a) Find c and E[X]. (b) What is the PMF of the random variable Z = (X – E[X])²? (c) Using the results from (b), find the variance of X. (d) Find the variance of X using the formula var(X) = Σx(x − E[X])²px(x).

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1. Let \( X \) be a random variable (RV) with probability mass function (PMF):

\[ P_X(x) = 
  \begin{cases} 
   \frac{x^2}{c} & \text{if } x = -3, -2, -1, 0, 1, 2, 3, \\
   0 & \text{otherwise.} 
  \end{cases} 
\]

Tasks:

(a) Find \( c \) and \( E[X] \).

(b) What is the PMF of the random variable \( Z = (X - E[X])^2 \)?

(c) Using the results from (b), find the variance of \( X \).

(d) Find the variance of \( X \) using the formula \(\text{var}(X) = \sum_x (x - E[X])^2 p_X(x)\).
Transcribed Image Text:1. Let \( X \) be a random variable (RV) with probability mass function (PMF): \[ P_X(x) = \begin{cases} \frac{x^2}{c} & \text{if } x = -3, -2, -1, 0, 1, 2, 3, \\ 0 & \text{otherwise.} \end{cases} \] Tasks: (a) Find \( c \) and \( E[X] \). (b) What is the PMF of the random variable \( Z = (X - E[X])^2 \)? (c) Using the results from (b), find the variance of \( X \). (d) Find the variance of \( X \) using the formula \(\text{var}(X) = \sum_x (x - E[X])^2 p_X(x)\).
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