Question

A quality-conscious disk manufacturer wishes to know the fraction of disks his company makes which are...

A quality-conscious disk manufacturer wishes to know the fraction of disks his company makes which are defective. Step 1 of 2: Suppose a sample of 985 floppy disks is drawn. Of these disks, 917 were not defective. Using the data, estimate the proportion of disks which are defective. Enter your answer as a fraction or a decimal number rounded to three decimal places.

Suppose a sample of 985 floppy disks is drawn. Of these disks, 917 were not defective. Using the data, construct the 85% confidence interval for the population proportion of disks which are defective. Round your answers to three decimal places.

0 0
Add a comment Improve this question Transcribed image text
Answer #1

Proportion of disks which are defective = Number of disks which are defective / Total number of disks

Total number of disks = 985

Number of disks which are defective = 985 - 917 = 68

Proportion of disks which are defective = p = 68 / 985 = 0.069

Now, we find the confidence interval for the population proportion of disks which are defective using the formula :

p(1 - p) Upper limit: p + Za/21

Lower limit: p -Z/1/p1-p)

We have p = 0.069

n = 985

a1-0.85-0.15

Using Standard Normal Tables we get :

alpha/2-Zo.15/2 Z0.075 1.44

Putting all the values in the above expression we get ,

Upper limit 0.069 1.1 0009-0.069) er (am 0.081 985

/ V 0.069(1 -0.069) 985 Lower limit = 0.069-1.44 = 0.057

So,  85% confidence interval for the population proportion of disks which are defective is : ( 0.057 , 0.081 )

Add a comment
Know the answer?
Add Answer to:
A quality-conscious disk manufacturer wishes to know the fraction of disks his company makes which are...
Your Answer:

Post as a guest

Your Name:

What's your source?

Earn Coins

Coins can be redeemed for fabulous gifts.

Not the answer you're looking for? Ask your own homework help question. Our experts will answer your question WITHIN MINUTES for Free.
Similar Homework Help Questions
ADVERTISEMENT
Free Homework Help App
Download From Google Play
Scan Your Homework
to Get Instant Free Answers
Need Online Homework Help?
Ask a Question
Get Answers For Free
Most questions answered within 3 hours.
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT