Questions: Dirty air: The federal government has enacted maximum allowable standards for air pollutants such as ozone. Let X be the number of days per year that the level of air pollution exceeds the standard in a certain city. The probability distribution of X is given by
x 0 1 2 3 4
P(x) 0.33 0.39 0.19 0.04 0.05
Transcript text: Dirty air: The federal government has enacted maximum allowable standards for air pollutants such as ozone. Let $X$ be the number of days per year that the level of air pollution exceeds the standard in a certain city. The probability distribution of $X$ is given by
\begin{tabular}{c|ccccc}
$x$ & 0 & 1 & 2 & 3 & 4 \\
\hline$P(x)$ & 0.33 & 0.39 & 0.19 & 0.04 & 0.05
\end{tabular}
Solution
Solution Steps
Step 1: Computing the Mean ($\mu_X$)
The mean ($\mu_X$) is computed using the formula:
\[
\mu_X = \sum_{i} x_i P(x_i)
\]
Substituting the given values, we get $\mu_X = 1.09$.
Step 2: Computing the Standard Deviation ($\sigma_X$)
The standard deviation ($\sigma_X$) is computed using the formula:
\[
\sigma_X = \sqrt{\sum_{i} (x_i - \mu_X)^2 P(x_i)}
\]
Substituting the given values and the computed mean, we get $\sigma_X = 1.06$.
Step 3: Computing Probabilities of Specific Outcomes
The probability of specific outcomes is computed by summing the probabilities of the desired outcomes.
For the given specific outcomes, the total probability is 0.28.
Final Answer:
The mean of the distribution is 1.09, the standard deviation is 1.06,
and the probability of the specific outcomes is 0.28.