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Get Full Access to Statistics For Engineers And Scientists - 4 Edition - Chapter 4.2 - Problem 19e
Get Full Access to Statistics For Engineers And Scientists - 4 Edition - Chapter 4.2 - Problem 19e

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# A certain large shipment comes with a guarantee that it

ISBN: 9780073401331 38

## Solution for problem 19E Chapter 4.2

Statistics for Engineers and Scientists | 4th Edition

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Problem 19E

A certain large shipment comes with a guarantee that it contains no more than 15% defective items. If the proportion of defective items in the shipment is greater than 15%, the shipment may be returned. You draw a random sample of 10 items. Let X be the number of defective items in the sample.

a. If in fact 15% of the items in the shipment are defective (so that the shipment is good, but just barely), what is P(X ≥ 7)?

b. Based on the answer to part (a), if 15% of the items in the shipment are defective, would 7 defectives in a sample of size 10 be an unusually large number?

c. If you found that 7 of the 10 sample items were defective, would this be convincing evidence that the shipment should be returned? Explain.

d. If in fact 15% of the items in the shipment are defective, what is

P(X ≥ 2)?

e. Based on the answer to part (d), if 15% of the items in the shipment are defective, would 2 defectives in a sample of size 10 be an unusually large number?

f. If you found that 2 of the 10 sample items were defective, would this be convincing evidence that the shipment should be returned? Explain.

Step-by-Step Solution:
Step 1 of 3

Solution 19E

Step1 of 7:

Let us consider a random variable X it presents number of defective items in the sample.

Then X follows binomial distribution with parameters “n and p” that is X B(n, p),

The probability mass function of binomial distribution is given by

, x = 0,1,2,...,n.

Where,

n = sample size

= 10

x = random variable

p = probability of success

= 0.15

q = 1 - p (probability of failure)

= 1 - 0.15

= 0.85

Here our goal is:

a).We need to find , when 15% of the items in the shipment are defective.

b).We need to check whether 7 defectives in a sample of size 10 be an unusually large number.

c).We need to check whether this would be convincing evidence that the shipment should be returned or not if yes explain.

d).We need to find , when 15% of the items in the shipment are defective.

e).We need to check whether 2 defectives in a sample of size 10 be an unusually large number.

f).We need to check whether this would be convincing evidence that the shipment should be returned or not if yes explain.

Step2 of 7:

a).

We have n = 10 and p = 0.15.

Here  can be obtained from Excel by using the function  “=binomdist(X,n,p,false)”

 X 7 0.0001259 8 0.000008332 9 0.0000003267 10 0.000000005766 Total 0.0001345

Therefore, 0.0001345.

Step3 of 7:

b).

From part (a), we have when 15% of the items in the shipment are defective then

0.0001345.

Now take n = 100000 then [n] = [100000]

= 13.45

13.

Hence, “Yes”,7 defectives in a sample of size 10 be an unusually large number.

Therefore out of 100000 samples have only 7 or more defective items.

Step4 of 7:

c).

“Yes”, because in part (b) we have seen that 7 defectives in a sample of size 10 be an unusually large number for good shipment

Step5 of 7:

d).

We have n = 10 and p = 0.15.

= 1 -

Here can be obtained from Excel by using the function  “=binomdist(X,n,p,false)”

 X 0 0.1968744043 1 0.3474254194 Total 0.5442998238

Now,

= 1 - 0.5442

= 0.4558

Therefore, 0.4558.

Step6 of 7:

e).

From part (d), we have when 15% of the items in the shipment are defective then

0.4558.

Now take n = 100 then [n] = [100]

= 45.58

45.

Hence, “No”, 2 defectives in a sample of size 10 be an unusually not large number because 45% of samples of size 10, 2 or more items are defective.

Step7 of 7:

f).

“No”, because in part (e) we have seen that 2 defectives in a sample of size 10 be an unusually not large number for good shipment.

Step 2 of 3

Step 3 of 3

##### ISBN: 9780073401331

The full step-by-step solution to problem: 19E from chapter: 4.2 was answered by , our top Statistics solution expert on 06/28/17, 11:15AM. This full solution covers the following key subjects: shipment, items, defective, sample, returned. This expansive textbook survival guide covers 153 chapters, and 2440 solutions. Statistics for Engineers and Scientists was written by and is associated to the ISBN: 9780073401331. This textbook survival guide was created for the textbook: Statistics for Engineers and Scientists , edition: 4. The answer to “A certain large shipment comes with a guarantee that it contains no more than 15% defective items. If the proportion of defective items in the shipment is greater than 15%, the shipment may be returned. You draw a random sample of 10 items. Let X be the number of defective items in the sample.a. If in fact 15% of the items in the shipment are defective (so that the shipment is good, but just barely), what is P(X ? 7)?________________b. Based on the answer to part (a), if 15% of the items in the shipment are defective, would 7 defectives in a sample of size 10 be an unusually large number?________________c. If you found that 7 of the 10 sample items were defective, would this be convincing evidence that the shipment should be returned? Explain.________________d. If in fact 15% of the items in the shipment are defective, what isP(X ? 2)?________________e. Based on the answer to part (d), if 15% of the items in the shipment are defective, would 2 defectives in a sample of size 10 be an unusually large number?________________f. If you found that 2 of the 10 sample items were defective, would this be convincing evidence that the shipment should be returned? Explain.” is broken down into a number of easy to follow steps, and 206 words. Since the solution to 19E from 4.2 chapter was answered, more than 676 students have viewed the full step-by-step answer.

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