Select the correct answer.

Tim works for a cell phone company and is testing their new biometric security feature. He conducted a test in which 4,000 attempts were made to unlock the phone. Of the attempts to unlock the phone, [tex]$25\%$[/tex] were made by someone other than the phone's owner. The results of the test are shown in the table.

\begin{tabular}{|c|c|c|c|}
\cline {2-4}
\multicolumn{1}{c|}{} & Unlocked & \begin{tabular}{c}
Did Not \\
Unlock
\end{tabular} & Total \\
\hline
Owner & 2,418 & 582 & 3,000 \\
\hline
Not the Owner & 232 & 768 & 1,000 \\
\hline
Total & 2,650 & 1,350 & 4,000 \\
\hline
\end{tabular}

What is the probability that someone who is able to unlock the phone using the biometric security feature is not the owner?

A. [tex]$8.8\%$[/tex]

B. [tex][tex]$9.6\%$[/tex][/tex]

C. [tex]$5.8\%$[/tex]

D. [tex]$6.2\%$[/tex]



Answer :

To determine the probability that someone who is able to unlock the phone using the biometric security feature is not the owner, we need to look at the data provided in the table and focus on those who successfully unlocked the phone.

From the table, we have the following information for successful unlock attempts:
- The total number of successful unlock attempts (both owner and not the owner) is 2,650.
- Out of these successful attempts, 2,418 were made by the owner.
- Out of these successful attempts, 232 were made by someone other than the owner.

To find the probability that someone who is able to unlock the phone is not the owner, we calculate the ratio of successful unlocks by non-owners to the total successful unlocks.

This ratio is given by:
[tex]\[ \text{Probability (not owner)} = \left(\frac{\text{number of successful unlocks by not the owner}}{\text{total number of successful unlocks}}\right) \times 100 \][/tex]

Plugging in the values from the table:
[tex]\[ \text{Probability (not owner)} = \left(\frac{232}{2650}\right) \times 100 \][/tex]

Evaluating this gives us:
[tex]\[ \text{Probability (not owner)} \approx 8.754716981132075 \][/tex]

Rounding this to one decimal place, we get:
[tex]\[ \text{Probability (not owner)} \approx 8.8\% \][/tex]

Therefore, the correct answer is:
A. [tex]$8.8 \%$[/tex]