Question

How's the economy? A pollster wants to construct a 95 % confidence interval for the proportion of adults who believe that economic conditions are getting better.

(a) A poll taken in July 2010 estimates this proportion to be 0.41 . Using this estimate, what sample size is needed so that the confidence interval will have a margin of error of 0.02 ?

(b) Estimate the sample size needed if no estimate of p is available. Part 1 of 2

(a) A poll taken in July 2010 estimates this proportion to be 0.41 . Using this estimate, what sample size is needed so that the confidence interval will have a margin of error of 0.02 ?

A sample of adults is needed to obtain a 95 % confidence interval with a margin of error of 0.02 . Part 2 of 2

(b) Estimate the sample size needed if no estimate of p is
available.

A sample of adults is needed to obtain a 95 % confidence interval
with a margin of error of 0.02

Answer #1

A
pollster wants to construct a 95% confidence interval for the
proportion of adults who believe that economic conditions are
getting better. A Gallup poll taken in July 2010 estimates this
proportion to be 0.33. Using this estimate, what sample size is
needed so that the confidence interval will have a margin of error
of 0.034 ?
Write only an integer as your answer .

A pollster wants to construct a 95% confidence interval for the
proportion of adults who believe that economic conditions are
getting better. A Gallup poll taken in July 2010 estimates this
proportion to be 0.33. Using this estimate, what sample size is
needed so that the confidence interval will have a margin of error
of 0.010 ? Write only an integer as your answer.

"Call me: A sociologist wants to construct a 95% confidence
interval for the proportion of children aged 8–12 living in NewYork
who own a cell phone.a. A survey by the National Consumers League
estimated the nationwide proportion to be 0.56. Using this
estimate, what sample size is needed so that the confidence
interval will have a margin of error of 0.02?b. Estimate the sample
size needed if no estimate of p is31. Changing jobs: A sociologist
sampled 200 people who...

Surgical complications: A medical researcher
wants to construct a 98% confidence interval for the proportion of
knee replacement surgeries that result in complications.
) Estimate the sample size needed if no estimate of
p
is available.
A sample of __operations is needed
to obtain a 98%confidence interval with a margin of error of 0.08
when no estimate of p is available.

A sociologist wants to construct a 95% confidence interval for
the proportion of children aged 8–12 living in New York who own a
cell phone. A survey estimated the nationwide proportion to be
0.56. What sample size is needed so that the confidence interval
will have a margin of error of 0.02? (Provide your answer as a
whole number).

Surgical complications: A medical researcher wants to construct
a 98% confidence interval for the proportion of knee replacement
surgeries that result in complications.
(a) An article in a medical journal suggested that approximately
20% of such operations result in complications. Using this
estimate, what sample size is needed so that the confidence
interval will have a margin of error of 0.08?
A sample of__?/ operations is needed to obtain a 98% confidence
interval with a margin of error of 0.08...

You want to construct a 95% confidence interval to estimate an
unknown population proportion with a margin of error of ±2%. What
is the minimum necessary sample size that you should obtain?

Assume that you want to construct a 95% confidence interval
estimate of a population mean. Find an estimate of the sample size
needed to obtain the specified margin of error for the 95%
confidence interval. The sample standard deviation is given
below.
Margin of errors=$6,
standard deviation=$22
The required sample size is __

What is the minimal sample size needed for a 95% confidence
interval to have a maximal margin of error of 0.02 if there is no
preliminary estimate for p?
A. 4161
B. 2401
C. 25
D. 1455
1455

What sample size would be needed to construct a 95% confidence
interval with a 5% margin of error on any population
proportion?
Give a whole number answer. (Of course.)

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