Question
In: Statistics and Probability
13. A television manufacturer takes a random sample of 30 customers and determines the times (after...
13.
A television manufacturer takes a random sample of 30
customers and determines the times (after purchasing) until the
televisions need servicing have a mean of 6 years and a standard
deviation of 1.2 years.
a) Determine the 95% confidence interval for the mean and
explain whether it is reasonable for the company to claim the mean
time until servicing is needed is 6.4 years.
b) Repeat a), but use a 90% interval.
c) Suppose instead a larger sample of 100 customers was taken
and it had the same mean and standard deviation as the sample of
30. Determine both the 90% and 95% confidence intervals. Does
either interval support the company’s claim that the mean time is
6.4 years until servicing is needed?
Solutions
Expert Solution
( a )
yes , it is reasonable for the company to claim the mean time until servicing is needed is 6.4 years. because
6.4 lies between 5.552 and 6.448
( b )
No , it is not reasonable for the company to claim the mean time until servicing is needed is 6.4 years. because
6.4 does not lies between 5.628 ad 6.372
( c )
No , it is not reasonable for the company to claim the mean time until servicing is needed is 6.4 years. because
6.4 does not lies between 5.762 and 6.238
No , it is not reasonable for the company to claim the mean time until servicing is needed is 6.4 years. because
6.4 does not lies between 5.801 and 6.199
orchestra answered 1 year agoRelated Solutions
A quality control specialist for a restaurant chain takes a random sample of size 13 to...
A quality control specialist for a restaurant chain takes a
random sample of size 13 to check the amount of soda served in the
16 oz. serving size. The sample mean is 13.30 with a sample
standard deviation of 1.54. Assume the underlying population is
normally distributed. We wish to construct a 95% confidence
interval for the true population mean for the amount of soda
served. What is the error bound? (Round your answer to two decimal
places.)
A certain gym selected a random sample of 10 customers and monitored the number of times...
A certain gym selected a random sample of 10 customers and
monitored the number of times each customer used the workout
facility in a one-month period. The data are shown in the table
below. The gym's managers are considering a promotion in which
they reward frequent users with a small gift. They have decided
that they will only give gifts to those customers whose number of
visits in a one-month period is 1 standard deviation above the
mean. Find the...
The Hiatus retail outlet takes a random sample of 25 customers from a segment population of...
The Hiatus retail outlet takes a random sample of 25 customers
from a segment population of 1,000 with a mean average transaction
size of $80 normally distributed with a known population standard
deviation of $20 per transaction. Find The 90% confidence interval
for transaction size, and The 95% confidence interval for
transaction size, and The 99% confidence interval for transaction
size. What do these results indicate for management?
A random sample of 16 pharmacy customers showed the waiting times below (in minutes). Also, the...
A random sample of 16 pharmacy customers showed the waiting
times below (in minutes). Also, the sample is from a normal
population. Note that σ is unknown. 21 22 22 17 21 17 23 20 20 24 9
22 16 21 22 21 The sample mean is 19.875 and the sample standard
deviation is 3.65. Which of the following represents the 80 percent
confidence interval for µ?
Select one:
a. [13.75, 25.25]
b. [18.65, 21.10]
c. [19.55, 20.425]
d. [18.8,...
Suppose a random sample of 30 customers is taken to test a company’s claim that 85%...
Suppose a random sample of 30 customers is taken to test a
company’s claim that 85% of customers are satisfied with their dog
food. Assume trials are independent. What is the probability at
least 22 customers are satisfied?
A random sample of 16 pharmacy customers showed the waiting times below (in minutes). 26 16...
A random sample of 16 pharmacy customers showed the waiting
times below (in minutes).
26
16
25
18
17
24
18
23
14
20
10
18
19
13
17
16
Click here for the Excel Data File
Find a 90 percent confidence interval for μ, assuming that
the sample is from a normal population. (Round your
standard deviation answer to 4 decimal places and t-value to 3
decimal places. Round your answers to 3 decimal
places.)
The 90% confidence...
Educational Television In a random sample of 186 people, 138 said that they watched educational television....
Educational Television In a random sample of
186 people, 138 said that they watched educational television. Find
the 94%confidence interval of the true proportion of people who
watched educational television. Use a graphing calculator. Round
the answers to at least three decimal places.
A simple random sample of 30 items resulted in a sample mean of 30. The population...
A simple random sample of 30 items resulted in a sample mean of
30. The population standard deviation is 15.
a. Compute the 95% confidence interval for the
population mean. Round your answers to one decimal place.
( , )
b. Assume that the same sample mean was
obtained from a sample of 120 items. Provide a 95% confidence
interval for the population mean. Round your answers to two decimal
places.
( , )
(a) Suppose that a random sample of 387 television ads in the United Kingdom reveals that...
(a) Suppose that a random sample of 387
television ads in the United Kingdom reveals that 131 of these ads
use humor. Find a point estimate of and a 95 percent confidence
interval for the proportion of all U.K. television ads that use
humor. (Round your answers to 3 decimal
places.)
pˆp^ = [ ]
The 95 percent confidence interval is [ , ].
(b) Suppose a random sample of 493 television
ads in the United States reveals that 134...
In a random sample of n = 500 families owning television sets in the city of...
In a random sample of n = 500 families owning television sets in
the city of Amman, Jordan, it is found that x = 340 subscribe to
Netflix service. 1- Find a 95% confidence interval for the true
proportion of families with television sets in this city that
subscribe to Netflix service. 2- If ˆp is used as an estimate of p,
can we be 95% confident that the error will not exceed 0.04.
Explain Part (b)- The weights, in...
ADVERTISEMENT
ADVERTISEMENT
Latest Questions
- What are the six steps of hypothesis testing? What does it mean if we reject the...
- Consider the following network of a project consisting of 7 activities with a scheduled project duration...
- In 1941, President Roosevelt spoke about the “four freedoms.” For many in the country, however, these...
- Your friend is looking for investors in a risky business venture. To convince you to participate,...
- Suppose you observe the following situation: State of Economy Probability of State Return if State Occurs...
- Merger Analysis TransWorld Communications Inc., a large telecommunications company, is evaluating the possible acquisition of Georgia...
- Journal Entries and Trial Balance Elite Realty acts as an agent in buying, selling, renting, and...
ADVERTISEMENT