Find the indicated probability.
-The following table show the results of a clinical trial for an allergy drug. $$\begin{array} { l | c | c | c | c }
& \begin{array} { c }
\text { Allergy } \
\text { drug }
\end{array} & \text { Placebo } & \begin{array} { c }
\text { Control } \
\text { (no treatment) }
\end{array} & \text { Total } \
\hline \text { Improvement } & 145 & 85 & 41 & 271 \
\text { No improvement } & 55 & 115 & 59 & 229 \
\text { Total } & 200 & 200 & 100 & 500
\end{array}$$ What is the probability that a randomly selected person was given a placebo or improved? Round your answer to the nearest thousandth when necessary.

Question

Find the indicated probability.
-The following table show the results of a clinical trial for an allergy drug. $$\begin{array} { l | c | c | c | c } 
& \begin{array} { c } 
\text { Allergy } \
\text { drug }
\end{array} & \text { Placebo } & \begin{array} { c } 
\text { Control } \
\text { (no treatment) }
\end{array} & \text { Total } \
\hline \text { Improvement } & 145 & 85 & 41 & 271 \
\text { No improvement } & 55 & 115 & 59 & 229 \
\text { Total } & 200 & 200 & 100 & 500
\end{array}$$ What is the probability that a randomly selected person was given a placebo or improved? Round your answer to the nearest thousandth when necessary.

Quizplus · Accepted Answer

The probability that a randomly selected person was given a placebo or improved is found by adding the number of people who were given a placebo (200) to the number of people who improved (271), and then subtracting the overlap (those who were given a placebo and improved, which is 85) to avoid double-counting. This gives us $200 + 271 - 85 = 386$. Then, we divide by the total number of people (500) to find the probability: $386 / 500 = 0.772$.

Find the Indicated Probability What Is the Probability That a Randomly Selected Person Was