Question

An
EPA investigator wants to determine the proportion of fish that are
inedible because of chemical pollution downstream of a factory.
Determine the number of fish that should be sampled in order for
the answer to be within +- 3% at the 99% confidence level. show all
work

Answer #1

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. ]

1. An investigator wants to determine if a new program aimed at
reducing the overall number of pregnancies in a highly-populated
area is effective (reducing average births below 6 per household).
In order to carry out the investigation, the investigator surveys
20 participants in the program and finds the average number of
births is 4.7 with a sample standard deviation of 0.9 births. a.
Carry out a test of hypothesis to test the investigator’s claim by
answering the following with...

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...

Suppose a marketing company wants to determine the current
proportion of customers who click on ads on their smartphones. It
was estimated that the current proportion of customers who click on
ads on their smartphones is 0.58. How many customers should the
company survey in order to be 99% confident that the margin of
error is 0.19 for the confidence interval of true proportion of
customers who click on ads on their smartphones?
(Round up your answer to nearest whole...

A local restaurant wants to determine what proportion of their
customers prefer red wine with dinner instead of white wine. If
they use a 99% level of confidence, how many customers do they need
to survey to be within 2.5% of the true proportion?

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...

Suppose the university wants to determine what proportion of
students prefer online tests to in-class tests. The university
invites the students to participate in a survey and out of 130
students that responded 39 prefer online testing.
(a)
Find the 90% confidence interval for the true proportion of
students that prefer online testing.
(b)
What is the minimum number of students that should answer the
survey in order to know with at least 98% certainty that the true
proportion of...

An automobile manufacturer wants to determine what proportion of
its customers are dissatisfied with the service received from their
local dealer. The manufacturer’s manager doesn’t have any estimate
for the proportion of dissatisfied customers. How many customers
should they sample if they want to be correct to within 4% of the
actual proportion with a 98% level of confidence?

Suppose a marketing company wants to determine the current
proportion of customers who click on ads on their smartphones. It
was estimated that the current proportion of customers who click on
ads on their smartphones is 0.65. How many customers should the
company survey in order to be 94% confident that the margin of
error is 0.22 for the confidence interval of true proportion of
customers who click on ads on their smartphones? Answer: (Round up
your answer to nearest...

A physical therapist wants to determine the difference in the
proportion of men and women who participate in regular sustained
physical activity. What sample size should be obtained if he wishes
the estimate to be within five percentage points with 99%
confidence, assuming that (a) he uses the estimates of 21.3%
male and 18.2% female from a previous year? (b) he does not use
any prior estimates?

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