If the population standard deviation of the lifetime of washing
machines is estimated to be 900...
If the population standard deviation of the lifetime of washing
machines is estimated to be 900 hours, how large a sample must be
taken in order to be 96% confident that the margin of error will
not exceed 100 hours?
Solutions
Expert Solution
The minimum sample is calculated as
N=344
Z is calculated using Z table shown below , normal curve
A dishwasher has a mean lifetime of 12 years with an estimated
standard deviation of 1.25 years. Assume the lifetime of a
dishwasher is normally distributed. Round the probabilities to four
decimal places. It is possible with rounding for a probability to
be 0.0000.
a) State the random variable. rv X = the lifetime of a randomly
selected dishwasher Correct
b) Find the probability that a randomly selected dishwasher has
a lifetime of 8.25 years or more.
c) Find the...
The manufacture of a washing powder product used in automatic
washing machines has estimated the following demand equation for
its product using data from 30 appliances stores around the
country.
Q= -350 - 2.0P + 1.2 Px + 5.0I + 6.0 A + 5.0U
(3.08) (0.60)
(0.55) (0.32) (0.80) (0.021) (SEC)
The actual values for each of the independent variables are as
follows. Assume the following information for the independent
variables:
Q = Quantity sold per month
Price (P) of...
A company sells washing machines for $340 each. To produce a
batch of n washing machines, there is a cost of $249 per washing
machine and a fixed or setup cost of $14,600 for the entire batch.
Determine a function that gives the profit in terms of the number
of washing machines produced. What is the least number of washing
machines the company can sell in order to have a profit of
$14,000?
Population 1 has an estimated mean of 50 and a sample standard
deviation of 3 while population 2 has a sample mean of 48 and a
sample standard deviation of 4. A sample of size 16 is taken for
each population.
Given that
the sample sizes are small, we have to "pool the variances,"
operating on the assumption that the variances are equal. What is
the value of pooled variance?
What is the
standard error of the difference in means,...
Population 1 has an estimated mean of 50 and a sample standard
deviation of 3 while population 2 has a sample mean of 48 and a
sample standard deviation of 4. A sample of size 16 is taken for
each population.
With the null being equality of means and the alternative being
that the means are not equal, the conclusion as to the equality of
means at the 90% level of confidence would be:
A.
Accept the null of no...
Population 1 has an estimated mean of 50 and a sample standard
deviation of 3 while population 2 has a sample mean of 48 and a
sample standard deviation of 4. A sample of size 16 is taken for
each population.
With the null being equality of means and the alternative being
that the means are not equal, the conclusion as to the equality of
means at the 90% level of confidence would be:
A.
Accept the null of no...
If the estimated lifetime benefit of a system is $870,000 and
the estimated lifetime cost of the system is $550,000.
What is the estimated lifetime Return On Investment (ROI)?
(First, state the
formula).
What is the annual percentage of the ROI if the estimated
cost/benefit is for 4 years duration?
c. What is the
real annual cash value of the system?
QUESTION 2
Now suppose Joyce doesn't have population standard deviation
(perhaps because these are new machines); she only has her sample
standard deviation which is 12. Using the same information, (500
grams average, sample mean of 495, sample size of 24), what are the
results of Joyce's analysis? (Check all that apply.) You will need
to use one of the tables available on Blackboard (knowing which one
is part of the question).
Fail to reject the null hypothesis.
Reject the...
1. What is the key difference between a population standard
deviation and the standard deviation of a sampling
distribution?
2. How does this effect the normal distribution for the sample?
(i.e. shape)
The average lifetime of a light bulb is 3000 hours with a
standard deviation of 696 hours. A simple random sample of 36 bulbs
is taken.
What is the probability that the average life in the sample will
be greater than 3219.24?
Note: respond in decimal form, for example, if your solution is
87.1234%, you should enter in 0.871234.