Mathematics, 24.03.2020 01:27 cajunldy2001

Suppose that bugs are present in 1% of all computer programs. A computer de-bugging program detects an actual bug with probability 0.99, but falsely detects a nonexistent bug with probability .02. Give numerical answers to each of the following questions:

(i) If the de-bugging program claims to have found a bug in program A, what is the probability that the bug is actually present?

(ii) Suppose that Program A is tested twice, the two tests conducted independently. If the de-bugging program claims that bugs are present on both the first and second tests, what is the probability that a bug is actually present?

(iii) Suppose that Program A is tested three times, the three tests conducted independently. If the de-bugging program claims that bugs are present on all three tests, what is the probability that a bug is actually present?

Answers: 1

Show answers

Answers

(i) The probability that there is a bug in the program given that the de-bugging program has detected the bug is 0.3333.

(ii) The probability that the bug is actually present given that the de-bugging program claims that bugs are present on both the first and second tests is 0.1111.

(iii) The probability that the bug is actually present given that the de-bugging program claims that bugs are present on all three tests is 0.037.

Step-by-step explanation:

Denote the events as follows:

B = bugs are present in a computer program.

D = a de-bugging program detects the bug.

The information provided is:

$P(B) =0.01\\P(D|B)=0.99\\P(D|B^{c})=0.02$

(i)

The probability that there is a bug in the program given that the de-bugging program has detected the bug is, P (B | D).

The Bayes' theorem states that the conditional probability of an event E given that another event X has already occurred is:

$P(E|X)=\frac{P(X|E)P(E)}{P(X|E)P(E)+P(X|E^{c})P(E^{c})}$

Use the Bayes' theorem to compute the value of P (B | D) as follows:

$P(B|D)=\frac{P(D|B)P(B)}{P(D|B)P(B)+P(D|B^{c})P(B^{c})}=\frac{(0.99\times 0.01)}{(0.99\times 0.01)+(0.02\times (1-0.01))}=0.3333$

Thus, the probability that there is a bug in the program given that the de-bugging program has detected the bug is 0.3333.

(ii)

The probability that a bug is actually present given that the de-bugging program claims that bug is present is:

P (B|D) = 0.3333

Now it is provided that two tests are performed on the program A.

Both the test are independent of each other.

The probability that the bug is actually present given that the de-bugging program claims that bugs are present on both the first and second tests is:

P (Bugs are actually present | Detects on both test) = P (B|D) × P (B|D)

$=0.3333\times 0.3333\\=0.11108889\\\approx 0.1111$

Thus, the probability that the bug is actually present given that the de-bugging program claims that bugs are present on both the first and second tests is 0.1111.

(iii)

Now it is provided that three tests are performed on the program A.

All the three tests are independent of each other.

The probability that the bug is actually present given that the de-bugging program claims that bugs are present on all three tests is:

P (Bugs are actually present | Detects on all 3 test)

= P (B|D) × P (B|D) × P (B|D)

$=0.3333\times 0.3333\times 0.3333\\=0.037025927037\\\approx 0.037$

Thus, the probability that the bug is actually present given that the de-bugging program claims that bugs are present on all three tests is 0.037.

Answer from: Quest

First one is 1 second one is 3

Answer from: Quest

$36\frac{9}{16}$

Another question on Mathematics

Mathematics, 21.06.2019 16:00

Asalesperson earns $320 per week plus 8% of her weekly sales. the expression representing her earnings is 320 + 0.08x. which of the following describes the sales necessary for the salesperson to earn at least $1000 in the one week?

Answers: 2

Answer

Mathematics, 21.06.2019 17:30

1mile equals approximately 1.6 kilometers. which best approximates the number of miles in 6 kilometers?

Answers: 1

Answer

Mathematics, 21.06.2019 19:30

Write a function rule for the table. hours worked pay 2 $16.00 4 $32.00 6 $48.00 8 $64.00 p = 16h p = 8.00h p = h + 16 h = 8.00p

Answers: 1

Answer

Mathematics, 21.06.2019 22:30

5, 6, 10 question: a. determine whether the side lengths form a triangle. (explain your reasoning) b. if it is a triangle, determine whether it is a right, acute, or obtuse triangle. (show your work)

Answers: 1

Answer

You know the right answer?

Suppose that bugs are present in 1% of all computer programs. A computer de-bugging program detects...

Questions

Mathematics, 18.07.2019 14:00

It is 2 miles from ellie’s house to school, 1 mile = 5280 feet. how many feet is it from ellie’s house to school ?...

Mathematics, 18.07.2019 14:00

Find the distance between but points a and b show me step by step...