Question

A simple random sample of 1600 persons is taken to estimate the percentage of Democrats among 25000 eligible voters in a certain town. It turns out that 856 people in the sample are Democrats. We can be 95 percent confident that between percent and percent of the voters are Democrats.

Answer #1

Solution :

Given that,

n = 1600

x = 856

Point estimate = sample proportion = = x / n = 856 / 1600 = 0.535

1 - = 0.465

Z_{/2}
= 1.96

Margin of error = E = Z_{
/ 2} *
((
* (1 -
)) / n)

= 1.96 * (((0.535 * 0.465) / 1600)

= 0.024

A 95% confidence interval for population proportion p is ,

- E < p < + E

0.535 - 0.024 < p < 0.535 + 0.024

0.511 < p < 0.559

We can be 95 percent confident that between 51.1% and 55.9% of the voters are Democrats .

A simple random sample of 1600 persons is taken to estimate the
percentage of Democrats among 25000 eligible voters in a certain
town. It turns out that 872 people in the sample are Democrats.
We can be 95 percent confident that between ...… percent and
........ percent of the voters are Democrats.

A simple random sample of 400 persons is taken to estimate the
percentage of women in the Boston Teacher's Union whose total
membership is 8000. Of those surveyed, 262 teachers are females. We
can be 95 percent confident that between percent and percent of the
teachers in the union are females.

A simple random sample of 400 persons is taken to estimate the
percentage of women in the Boston Teacher's Union whose total
membership is 8000. Of those surveyed, 273 teachers are females. We
can be 95 percent confident that between...……. percent and
...............percent of the teachers in the union are
females.

In a certain town, there are 4,000 registered voters, of whom
1,600 are Democrats. A survey organization is about to take a
random sample of 100 registered voters.
(a) There is about a 50-50 chance that the percentage of
Democrats in the sample will be bigger than _____.
(b) Find the expected value for the sample percentage,
(c) Find the standard error for the sample percentage.
(d) Find the chance that 30% or more of the people in sample are...

A college has 25000 students. Based on student personal
information data, approximately 55 percent are Democrats. A simple
random sample of 900 households were selected for a survey. The
percentage of Democrats in the sample will be around 55, give or
take 1.66 or so.
Estimate the chance that between 52.45 percent and 57.55 percent
of the students in the sample are Democrats.
Answer is not 0.000 !!!!

A college has 25000
students. Based on student personal information data, approximately
55 percent are Democrats. A simple random sample of 900 households
were selected for a survey. The percentage of Democrats in the
sample will be around 55% , give or take 1.66% or so.
Estimate the chance
that between 42.45 percent and 47.55 percent of the students in the
sample are Democrats_________.

In a large city, we are trying to estimate the percentage of
college enrollment among all people of age between 18 and 24. (So
our population is people of age between 18 and 24 in this city.) We
take a simple random sample of 192 from this population. In this
sample, we find that 77 are enrolled in college. Find a 95%
confidence interval for the rate of college enrollment in the
population. (Only enter the upper limit as your...

In a large city, we are trying to estimate the percentage of
college enrollment among all people of age between 18 and 24. (So
our population is people of age between 18 and 24 in this city.) We
take a simple random sample of 197 from this population. In this
sample, we find that 76 are enrolled in college. Find a 95%
confidence interval for the rate of college enrollment in the
population. (Only enter the upper limit as your...

A random sample of 1,175 people in a certain country were asked
whether they thought climate change was a problem. The sample
proportion of those who think climate change is a problem was
calculated, and a 95 percent confidence interval was constructed as
(0.146, 0.214). Which of the following is a correct interpretation
of the interval?
a) We are 95 percent confident that any sample of 1,175 people
will produce a sample proportion between 0.146 and 0.214.
B)We are 95...

Let's say we want to estimate the population proportion of a
population. A simple random sample of size 400 is taken from the
population. If the sample proportion is 0.32:
1) what is the point estimate of the population proportion?
2) At the 95% level of confidence, what is the margin of
error?
3) Based on 2) what is a confidence interval at the 95%
confidence level?
4) What is the margin of error if the level of confidence is...

ADVERTISEMENT

Get Answers For Free

Most questions answered within 1 hours.

ADVERTISEMENT

asked 1 minute ago

asked 6 minutes ago

asked 6 minutes ago

asked 8 minutes ago

asked 14 minutes ago

asked 15 minutes ago

asked 15 minutes ago

asked 22 minutes ago

asked 26 minutes ago

asked 48 minutes ago

asked 48 minutes ago

asked 51 minutes ago