Question 2 Let X be a discrete random variable with probability mass function given by 1 2 3 p(x) 1/4 1/2 1/8 1/8 a) Estimate P(X < 1). Answer: в «- 1000 x <- replicate(B, sample( c(0, 1, 2, 3), 1, prob = c(1/4, 1/2, 1/8, 1/8) ) mean (x <= 1) ## [1] 0.76 # answer (1/4) + (1/2) ## [1] 0.75 b) Find P(X <1|X < 2). Answer: B <- 1000 x <- replicate (B, sample( c(0, 1, 2, 3), 1, prob = c(1/4, 1/2, 1/8, 1/8) ), y <- replicate(B, sample( c(0, 1, 2, 3), 1, prob = c(1/4, 1/2, 1/8, 1/8) ) mean (x <= 1)/mean (y <= 2)

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Question 2

Let \( X \) be a discrete random variable with probability mass function given by

\[
\begin{array}{c|cccc}
x & 0 & 1 & 2 & 3 \\
\hline
p(x) & 1/4 & 1/2 & 1/8 & 1/8 \\
\end{array}
\]

a) Estimate \( P(X \leq 1) \).

**Answer:**

```R
B <- 1000

x <- replicate(B,
  sample(c(0, 1, 2, 3), 1, prob = c(1/4, 1/2, 1/8, 1/8))
)

mean(x <= 1)
```

Output:
```
## [1] 0.76
```

**Theoretical Calculation:**

\[
P(X \leq 1) = (1/4) + (1/2)
\]

Output:
```
## [1] 0.75
```

b) Find \( P(X \leq 1 \mid X \leq 2) \).

**Answer:**

```R
B <- 1000

x <- replicate(B,
  sample(c(0, 1, 2, 3), 1, prob = c(1/4, 1/2, 1/8, 1/8))
)

y <- replicate(B,
  sample(c(0, 1, 2, 3), 1, prob = c(1/4, 1/2, 1/8, 1/8))
)

mean(x <= 1)/mean(y <= 2)
```

Output:
```
## [1] 0.8963134
```

**Theoretical Calculation:**

\[
P(X \leq 1 \mid X \leq 2) = \frac{(1/4 + 1/2)}{(1/4 + 1/2 + 1/8)}
\]

Output:
```
## [1] 0.8571429
```

**Explanation:**

This section demonstrates estimating probabilities for the discrete random variable \( X \) using simulation and theoretical calculations. Part (a) estimates the probability of \( X \) being less than or equal to
Transcribed Image Text:Question 2 Let \( X \) be a discrete random variable with probability mass function given by \[ \begin{array}{c|cccc} x & 0 & 1 & 2 & 3 \\ \hline p(x) & 1/4 & 1/2 & 1/8 & 1/8 \\ \end{array} \] a) Estimate \( P(X \leq 1) \). **Answer:** ```R B <- 1000 x <- replicate(B, sample(c(0, 1, 2, 3), 1, prob = c(1/4, 1/2, 1/8, 1/8)) ) mean(x <= 1) ``` Output: ``` ## [1] 0.76 ``` **Theoretical Calculation:** \[ P(X \leq 1) = (1/4) + (1/2) \] Output: ``` ## [1] 0.75 ``` b) Find \( P(X \leq 1 \mid X \leq 2) \). **Answer:** ```R B <- 1000 x <- replicate(B, sample(c(0, 1, 2, 3), 1, prob = c(1/4, 1/2, 1/8, 1/8)) ) y <- replicate(B, sample(c(0, 1, 2, 3), 1, prob = c(1/4, 1/2, 1/8, 1/8)) ) mean(x <= 1)/mean(y <= 2) ``` Output: ``` ## [1] 0.8963134 ``` **Theoretical Calculation:** \[ P(X \leq 1 \mid X \leq 2) = \frac{(1/4 + 1/2)}{(1/4 + 1/2 + 1/8)} \] Output: ``` ## [1] 0.8571429 ``` **Explanation:** This section demonstrates estimating probabilities for the discrete random variable \( X \) using simulation and theoretical calculations. Part (a) estimates the probability of \( X \) being less than or equal to
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