Among 8846 cases of heart pacemaker​ malfunctions, 375 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 8846 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?

Respuesta :

Step-by-step explanation:

Probability, P = [tex]\frac{no. of favourable outcomes}{Total no. of possible outcomes}[/tex]

Out of 8846 heart pacemaker malfunctions cases, caused by firmware cases are 375

then, no. of cases not caused by firmware are:

8846 - 375 = 8471

Probability for three different pacemakers respectively is given by:

P(1) = [tex]\frac{8471}{8846}[/tex]

we select the next malfunctioned pacemaker from the remaining i.e., out of 8471, excluding the chosen malfunctioned pacemaker

P(2|1) =  [tex]\frac{8470}{8845}[/tex]

Therefore, the events are not independent of each other

Now, if the selection is without replacement, then

P(3|1 & 2) =  [tex]\frac{8469}{8844}[/tex]

Now, by general multiplication rule(as the events are not independent):

P(none of the 3 are caused by malfunction) =

[tex]\frac{8471}{8846}\times\frac{8470}{8845}\times\frac{8469}{8844}[/tex]

= 0.9019

P(none of the 3 are caused by malfunction)  = 90.19%

The probability is high, therefore the whole batch will be accepted.

Probability of an event represents the chances of that event to occur.

  • The probability of the entire batch to get selected is 0.879
  • Yes, this procedure is likely to result in the entire batch being accepted.

What is the multiplication rule of probability for independent events?

Suppose there are n mutually independent events.

The probability of their simultaneously occurrence is given as

[tex]P(A_1 \cap A_2 \cap ... \cap A_n) = P(A_1) \times P(A_2) \times ... \times P(A_n)[/tex]

(This is true only if all those events are mutually independent).

The probability of getting a failure(malfunction) in a randomly selected pacemaker for the given case is

[tex]\dfrac{375}{8846} \approx 0.042[/tex]

The probability of a pacemaker working fine = 1- its failure probability  = 1 - 0.042 = 0.958

Since each of the 3 selected pacemakers are independent for their failure or success of each other, thus, if we have:

[tex]A_1[/tex] = Event of properly working of first pacemaker

[tex]A_2[/tex] = Event of properly working of second pacemaker

[tex]A_3[/tex] = Event of properly working of third pacemaker

Then, as all three are independent for their working from each other, thus,

[tex]P(A_1 \cap A_2 \cap A_3) = P(A_1) \times P(A_2)\times P(A_3) = (0.958)^3 \approx 0.879\\\\\begin{aligned}{P(\text{batch getting selected}) &= P(\text{All three pacemaker working})\\& = P(A_1 \cap A_2 \cap A_3) \\&\approx 0.879\\\end{aligned}[/tex]

Thus, as this probability is high, thus, this procedure is likely to result in the entire batch being accepted.

Thus,

  • The probability of the entire batch to get selected is 0.879
  • Yes, this procedure is likely to result in the entire batch being accepted.

Learn more about multiplication rule of probability here:

https://brainly.com/question/14399918