Q:

Among 6411 cases of heart pacemaker​ malfunctions, 340 were found to be caused by​ firmware, which is software programmed into the device. If the firmware is tested in 3 different pacemakers randomly selected from this batch of 6411 and the entire batch is accepted if there are no​ failures, what is the probability that the firmware in the entire batch will be​ accepted? Is this procedure likely to result in the entire batch being​ accepted? What is the probability? The procedure is what to result in the entire batch being accepted?

Accepted Solution

A:
To find the probability that the firmware in the entire batch will be accepted, we need to first find the probability of no failures in the selected 3 pacemakers.

The probability of no failure in a single pacemaker is given by:

$$P(\text{No failure in a single pacemaker}) = 1 - P(\text{Failure in a single pacemaker})$$

Given that there are 6411 cases of heart pacemaker malfunctions and 340 were found to be caused by firmware, the probability of failure in a single pacemaker is:

$$P(\text{Failure in a single pacemaker}) = \frac{340}{6411}$$

Therefore, the probability of no failure in a single pacemaker is:

$$P(\text{No failure in a single pacemaker}) = 1 - \frac{340}{6411}$$

Now, we need to find the probability of no failure in 3 different pacemakers. Since these pacemakers are randomly selected, we use the multiplication rule for independent events. The probability of no failure in 3 different pacemakers is:

$$P(\text{No failure in 3 different pacemakers}) = \left(1 - \frac{340}{6411}\right)^3$$

So, the probability that the firmware in the entire batch will be accepted is:

$$\text{Probability}=\left(1-\frac{340}{6411}\right)^3=0.8492$$

This procedure is likely to result in the entire batch being accepted because probability 0.8492 is close to 1.