Question

A random sample of 49 teenagers from a large population was surveyed, and the average number of movies that they had rented in the past week was x = 1.9, with a sample standard deviation of s = 0.5. a) Construct a 95% confidence interval for the average number of movies rented by teenagers in a week. b) Construct a 99% confidence interval for the average number of movies rented by teenagers in a week.t v

Answer #1

It is given that the sample size, n=49(>30), sample mean=x̅ = 1.9 and sample standard deviation= s=0.5

Here, since the sample size is large enough (>30), we can estimate population standard deviation σ= s=0.5 and to find a confidence interval, we will use Z-test which is as below:

A random sample of 49 teenagers from a large population was
surveyed, and the average number of movies that they had rented in
the past week was x = 1.9, with a sample standard deviation of s =
0.5.
a) Construct a 95% confidence interval for the average number of
movies rented by teenagers in a week.
b) Construct a 99% confidence interval for the average number of
movies rented by teenagers in a week.

A random sample of 49 teenagers from a large population was
surveyed, and the average number of movies that they had rented in
the past week was x = 1.9, with a sample standard deviation of s =
0.5. a) Construct a 95% confidence interval for the average number
of movies rented by teenagers in a week. b) Construct a 99%
confidence interval for the average number of movies rented by
teenagers in a week.

Question 1 A random sample of 49 teenagers from a large
population was surveyed, and the average number of movies that they
had rented in the past week was x = 1.9, with a sample standard
deviation of s = 0.5.
a) Construct a 95% confidence interval for the average number of
movies rented by teenagers in a week
. b) Construct a 99% confidence interval for the average number
of movies rented by teenagers in a week.

A random sample of 800 teenagers revealed that in this sample,
the mean number of hours per week of TV watching is 13.2 with a
sample standard deviation of 1.6. Find and interpret a 95%
confidence interval for the true mean weekly hours of TV watching
for teenagers.

A random sample of 49 lunch customers was selected at a
restaurant. The average amount of time the customers in the sample
stayed in the restaurant was 40 minutes. From past experience, it
is known that the population standard deviation equals 10
minutes.
a.
Compute the standard error of the mean.
b.
Construct a 95% confidence interval for the true
average amount of time customers spent in the restaurant.
c.
With a .95 probability, what sample size would have to...

An
Atlanta restaurant surveyed 49 diners at random, in order to
determine the mean population expenditure at the restaurant for
each mean. The restaurant wants to estimate the population mean
with 95% confidence level.
Given the following:
X-bar = $49
Population Standard Deviation = $5
Determine the margin of error. Determine the appropriate
confidence interval.

The mean number of hours of part-time work per week for a sample
of 317 teenagers is 29. If the margin of error for the population
mean with a 95% confidence interval is 2.1, construct a 95%
confidence interval for the mean number of hours of part-time work
per week for all teenagers.

the employees of cybertronics, inc. need to complete a
certification online. a random sample of 49 employees gives an
average time for completion of all coursework and passing the tests
of 6 hours. assume the population standard deviation is 6 hours and
the sample standard deviation is 6 hours. assume that the
population standard deviation is 6 hours and the population of
employees is fairly large. construct a 95% confidence interval for
the average time required to complete the certification.

the employees of cybertronics, inc. need to complete a
certification online. a random sample of 49 employees gives an
average time for completion of all coursework and passing the tests
of 6 hours. assume the population standard deviation is 6 hours and
the population of employees is fairly large. construct a 95%
confidence interval for the average time required to complete the
certification.

A random sample of 100 workers in one large plant took an
average of 12 minutes to complete a task, with a standard deviation
of 2 minutes. A random sample of 50 workers in a second large plant
took an average of 11 minutes to complete the task, with a standard
deviation of 3 minutes. Construct a 95% confidence interval for the
difference between the two population mean completion times.

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