Question

A manufacturer produces intraocular lenses. A sample of 300 lenses is obtained which contain 7 defective ones from a polishing machine a. Find the confidence interval for the defective fraction of the polisher with 95% confidence. b.Determine the sample size so that with 95% confidence we have an error in estimating the proportion of 0.016

Answer #1

A manufacturer wants to estimate the proportion of defective
items in production.18 out of 8,000 randomly sampled items are
found to be defective.
a) Establish a 99% confidence interval for the proportion of
defective items.
b) If we had constructed a confidence interval for the
proportion of non-defective items from of the same data, would we
have obtained a greater margin of error?
c) A proportion of defective items of 3/1000 is considered
acceptable. Are we sure of meet the...

A manufacturer of cell phones wants to estimate the proportion
of the defective phones the factory produces.
How many cell phones
should be sampled and checked in order to estimate the proportion
of the defective phones in the population to be within
4% margin of error with 99%
confidence? [This is a sample size determination
question for proportion. ]

LCD screen manufacturer tests a random sample of 500 screens and
finds 32 defective units.
a) (7 pts) Find a 98% confidence interval to estimate the
proportion of defective units and indicate the margin of error for
your estimate.
b) (5 pts) What should be the size of the sample to obtain a
maximum margin of error of 0.02, with a confidence level of
98%?
c) (5 pts) Assume that the sample is taken from a batch of 4000
LCD...

A computer chip manufacturer tests a random sample of 500 chips
in a 4000 lot and finds 32 defective units.
a) Find a 95% confidence interval to estimate the proportion of
defective units and calculate the margin of error for your
estimate.
b) Find a 95% confidence interval to estimate the total number of
defective units and calculate the margin of error for your
estimate.
Answers:
a. [0.04393,0.08407], m.e. = 0.02, b. [175,337], m.e. = 81

The fraction of defective integrated circuits produced
in a photolithography process is being studied. A random sample of
300 circuits is tested, revealing 18 defectives.
(a) Use the data to test the hypothesis that the
proportion is not 0.04. Use α = 0.05.
(b) Find the P-value for the test.
(c) Find a 95% two-sided traditional CI on the
proportion defective.
(d) Use the CI found in part (c) to test the
hypothesis.
(e) Suppose that the fraction defective is...

A light bulb manufacturer wants to estimate the proportion of
light bulbs being produced that are defective. A random sample of
155 light bulbs is selected and 12 are defective. Write the
interval (Show all work and circle your final answer), and
a. Find the sample proportion ?̂.
b. Create a 95% confidence interval (round to 3 decimal places)
for the population proportion of defective lightbulbs being
produced.
c. Write a sentence interpreting this.
d. Using the sample proportion from...

A quality-conscious disk manufacturer wishes to know the
fraction of disks his company makes which are defective.
Step 2 of 2 :
Suppose a sample of 10871087 floppy disks is drawn. Of these
disks, 108 were defective. Using the data, construct the 95%
confidence interval for the population proportion of disks which
are defective. Round your answers to three decimal places.

What Influences the Sample Size? We examine the effect of
different inputs on determining the sample size needed to obtain a
specific margin of error when finding a confidence interval for a
proportion.
Find the sample size needed to give, with 95% confidence, a
margin of error within ± 6% when estimating a proportion. Within ±
4% . Within ± 1% . (Assume no prior knowledge about the population
proportion p .) Round your answers up to the nearest integer....

A quality-conscious disk manufacturer wishes to know the
fraction of disks his company makes which are defective. Step 2 of
2 : Suppose a sample of 707 floppy disks is drawn. Of these disks,
77 were defective. Using the data, construct the 95% confidence
interval for the population proportion of disks which are
defective. Round your answers to three decimal places.
lower endpoint_________ upper endpoint___________

5. Mean of 1500, standard deviation of 300. Estimating the
average SAT score, limit the margin of error to 95% confidence
interval to 25 points, how many students to sample?
6. Population proportion is 43%, would like to be 95% confident
that your estimate is within 4.5% of the true population
proportion. How large of a sample is required?
7. P(z<1.34) (four decimal places)
8. Candidate only wants a 2.5% margin error at a 97.5%
confidence level, what size of...

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