Questions: Counting and Probability
Probabilities of an event and its complement
1 2 3 4 5 6 7 8 9 10
------------------------------------
X P(X)=1/5
not X P(not X)=4/5
(b) Subtract.
1-P(x)=4/5
(c) Select the answer that makes the sentence true.
1-P(X) is the same as (Choose one)
P(not X)
1-P(not X)
None of the above
Transcript text: Counting and Probability
Probabilities of an event and its complement
\begin{tabular}{|c|c|c|c|c|c|c|c|c|c|c|c|c|}
\hline \multicolumn{1}{|c|}{} & \multicolumn{7}{|c|}{ Putcomes } \\
\hline & 1 & 2 & 3 & 4 & 5 & 6 & 7 & 8 & 9 & 10 & \\
\hline$X$ & $\square$ & $\square$ & $\square$ & $\square$ & $\square$ & $\square$ & $\square$ & $\square$ & $\square$ & $\square$ & $P(X)=\frac{1}{5}$ \\
\hline not $X$ & $\square$ & $\square$ & $\square$ & $\square$ & $\square$ & $\square$ & $\square$ & $\square$ & $\square$ & $\square$ & $P(\operatorname{not} X)=\frac{4}{5}$ \\
\hline
\end{tabular}
(b) Subtract.
$1-P(x)=\frac{4}{5}$
(c) Select the answer that makes the sentence true.
$1-P(X)$ is the same as $\square$ (Choose one)
$P(\operatorname{not} X)$
$1-P(\operatorname{not} X)$
None of the above
Solution
Solution Steps
Solution Approach
Part (b): To find \(1 - P(X)\), we subtract the probability of event \(X\) from 1. Given \(P(X) = \frac{1}{5}\), we calculate \(1 - \frac{1}{5}\).
Part (c): We need to determine which option is equivalent to \(1 - P(X)\). Since \(1 - P(X)\) is the probability of the complement of \(X\), it should be equal to \(P(\text{not } X)\).
Step 1: Calculate \(1 - P(X)\)
Given that \(P(X) = \frac{1}{5}\), we calculate the complement probability as follows:
\[
1 - P(X) = 1 - \frac{1}{5} = \frac{5}{5} - \frac{1}{5} = \frac{4}{5}
\]
Step 2: Determine the Equivalent Expression
We need to determine which option is equivalent to \(1 - P(X)\). Since \(1 - P(X) = \frac{4}{5}\) and \(P(\text{not } X) = \frac{4}{5}\), it follows that:
\[
1 - P(X) = P(\text{not } X)
\]
Final Answer
For part (b), the result is:
\[
\boxed{1 - P(X) = \frac{4}{5}}
\]
For part (c), the correct choice is:
\[
\boxed{P(\text{not } X)}
\]