Question 4 (Multiple Choice, Worth 3 points)

During a thunderstorm at a sports event, a detector activates to let participants know there is lightning in the area so people can seek shelter. The accuracy of the lightning detector is summarized in the table below.

\begin{tabular}{|c|l|l|l|}
\hline
& Lightning detector activates & Lightning detector does not activate & Row Totals \\
\hline
Lightning in area & [tex]$88\%$[/tex] & [tex]$2\%$[/tex] & [tex]$90\%$[/tex] \\
\hline
No lightning in area & [tex]$7\%$[/tex] & [tex]$3\%$[/tex] & [tex]$10\%$[/tex] \\
\hline
Column Totals & [tex]$95\%$[/tex] & [tex]$5\%$[/tex] & [tex]$100\%$[/tex] \\
\hline
\end{tabular}

What is the ratio of true positives to false positives in this scenario? Round your answer to one decimal place.

A. 0.1

B. 1.5

C. 12.6



Answer :

To find the ratio of true positives to false positives, let's break down the problem step by step:

1. Understand the Given Data:
- True Positive Rate: 88% (When there is lightning, the detector activates 88% of the time).
- False Positive Rate: 7% (When there is no lightning, the detector activates 7% of the time).

2. Calculate the Ratio:
We need to determine the ratio of true positives to false positives. This can be calculated using the formula:
[tex]\[ \text{Ratio of True Positives to False Positives} = \frac{\text{True Positive Rate}}{\text{False Positive Rate}} \][/tex]
Substituting the given values:
[tex]\[ \text{Ratio of True Positives to False Positives} = \frac{88\%}{7\%} \][/tex]

3. Perform the Division:
[tex]\[ \frac{88}{7} \approx 12.571428571428571 \][/tex]

4. Round the Ratio to One Decimal Place:
When we round 12.571428571428571 to one decimal place, we get 12.6.

Therefore, the ratio of true positives to false positives in this scenario, rounded to one decimal place, is [tex]\( \boxed{12.6} \)[/tex].