From e0af86bf58e0700f770e8c1d7799739388e948ae Mon Sep 17 00:00:00 2001 From: Kmart Date: Tue, 16 Jan 2024 13:10:31 -0800 Subject: [PATCH] minor update to 2-d-1 --- _problems/unit-02/D-cdf-of-a-discrete-RV/1.md | 20 +++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) diff --git a/_problems/unit-02/D-cdf-of-a-discrete-RV/1.md b/_problems/unit-02/D-cdf-of-a-discrete-RV/1.md index c6d043e..0ab3544 100644 --- a/_problems/unit-02/D-cdf-of-a-discrete-RV/1.md +++ b/_problems/unit-02/D-cdf-of-a-discrete-RV/1.md @@ -53,7 +53,7 @@ To construct the pmf for $X$ let's compute the probability for possible value of As a check on this table, if represents a legitimate pmf for $X$, we see that for all values making up the supp($X$) the probabilities are greater than 0 and the sum of the probabilities is = 1. -So, the soution to part 1 is +So, the soution to **part 1** is $$ \Rightarrow X \in \\{ 0, 1, 2, 3, 4 \\} \text{, the pmf in bracket notation is: } @@ -63,14 +63,14 @@ $$ P(X=x) = \begin{cases} 0.0625, &x = 0\\\\ 0.25, &x = 1\\\\ 0.375, &x = 2\\\\ 0.25, &x = 3\\\\ 0.0625, &x = 4\\\\ 0, &otherwise\end{cases} $$ -For part 2 ... +For **part 2** ... $$ P(\text{ X is odd }) \Rightarrow P(\text{ X = 1 or X = 3 }) = \text{ (By Independence) } P(X = 1) + P( X = 3) = 0.5 $$ -Finally for part 3 we can compute the cdf $\( F_{X}(x) \)$ for $X$ by recalling that +Finally for **part 3** we can compute the cdf $\( F_{X}(x) \)$ for $X$ by recalling that $$ \( F_{X}(x) \) :== P(X \leq x) @@ -81,16 +81,16 @@ That is we sum all the mass from $\( -\infty \)$ to desired value of $x$ and rec $$ F_{X}(x) = \begin{cases} -0 & \text{if } x < 0 \\\\ -0.0625 & \text{if } 0 \leq x < 1 \\\\ -0.3125 & \text{if } 1 \leq x < 2 \\\\ -0.6875 & \text{if } 2 \leq x < 3 \\\\ -0.9375 & \text{if } 3 \leq x < 4 \\\\ -1 & \text{if } 4 \leq x \\\\ + 0 & \text{if } x < 0 \\\\ + 0.0625 & \text{if } 0 \leq x < 1 \\\\ + 0.3125 & \text{if } 1 \leq x < 2 \\\\ + 0.6875 & \text{if } 2 \leq x < 3 \\\\ + 0.9375 & \text{if } 3 \leq x < 4 \\\\ + 1 & \text{if } 4 \leq x \\\\ \end{cases} $$ -For part 4 we can just read off of the cdf in bracket notation +For **part 4** we can just read off of the cdf in bracket notation $$ P(X \leq 2) \text{ is the sum of the probability mass values at 0, 1, 2 or from the bracket notation = } 0.6875