Nate downloaded a free virus detection program, which reported that his computer is infected with a virus. The editors of a tech magazine reviewed the effectiveness of the free program by running it on 500 computers, with [tex]$8 \%$[/tex] of those computers being virus-infected. Their findings are summarized in the two-way table below:

\begin{tabular}{|c|c|c|}
\cline{2-3} \multicolumn{1}{c|}{} & Virus Reported & Virus Not Reported \\
\hline Infected & 28 & 12 \\
\hline Not Infected & 94 & 366 \\
\hline
\end{tabular}

Which statement is supported by the data?

A. The magazine's review suggests Nate should use a different detection program because the probability of a false positive is [tex]$92.89\%$[/tex].

B. The magazine's review suggests Nate should use a different detection program because the probability of a false positive is [tex]$77.05\%$[/tex].

C. The magazine's review suggests Nate should trust the program's report because the probability of a positive result is only [tex]$7.11\%$[/tex].

D. The magazine's review suggests Nate should use a different detection program because the probability of a false positive is [tex]$22.95\%$[/tex].



Answer :

To determine which statement is supported by the data, we need to analyze the false positive rate based on the given data. Here is a step-by-step solution:

1. Number of Computers Tested:
Total number of computers tested:
[tex]\[ \text{Total computers} = 500 \][/tex]

2. Number of Infected and Not Infected Computers:
- Number of computers infected with the virus:
[tex]\[ 28 + 12 = 40 \][/tex]

- Number of computers not infected with the virus:
[tex]\[ 94 + 366 = 460 \][/tex]

3. False Positives:
These are computers which the program reported as infected, but they were actually not infected. From the table:
[tex]\[ \text{False positives} = 94 \][/tex]

4. False Positive Rate Calculation:
The false positive rate is calculated as the number of false positives divided by the total number of non-infected computers, multiplied by 100 to convert it to a percentage:
[tex]\[ \text{False positive rate} = \left(\frac{\text{False positives}}{\text{Number of not infected}}\right) \times 100 \][/tex]
So, substitute the values we have:
[tex]\[ \text{False positive rate} = \left(\frac{94}{460}\right) \times 100 \approx 20.43\% \][/tex]

Conclusion:
The calculated false positive rate is approximately [tex]\(20.43\%\)[/tex].

Based on the provided statements:
- Statement D matches the calculated false positive rate statement, but with a small difference in percentage (22.95% instead of 20.43%).

Therefore, none of the statements perfectly matches the specific calculated false positive rate of [tex]\(20.43\%\)[/tex]. However, if we are to choose the closest one among the provided options, we'd say:

D. The magazine's review suggests Nate should use a different detection program because the probability that the scan false positive is [tex]\(22.95\%\)[/tex].

This choice is closest to the actual false positive rate calculated from the given data.

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