Question
In: Statistics and Probability
A lawn mower manufacturer is trying to determine the standard deviation of the mean life of...
A lawn mower manufacturer is trying to determine the standard deviation of the mean life of one of its lawn mower models. To do this, it randomly selects 12 lawn mowers that sold several years ago and finds that the sample standard deviation is 3.25 years (assume it was normally distributed). Construct a 99% confidence interval for the population standard deviation, σ
please show work
Solutions
Expert Solution
Solution :
Given that,
s = 3.25
s2 = 1.8028
n = 12
Degrees of freedom = df = n - 1 = 12 - 1 = 11
At 99% confidence level the 
2 value is ,
= 1 - 99% = 1 - 0.99 = 0.01
/ 2 = 0.01 / 2 = 0.005
1 -
/ 2 = 1 - 0.005 = 0.995
2L
=
2/2,df
= 26.757
2R
=
21 -
/2,df = 2.603
The 99% confidence interval for 
is,
(n
- 1)s2 /
2/2
<
<
(n - 1)s2 /
21 -
/2
(11)(1.8028)
/ 26.757 <
<
(11)(1.8028) / 2.603
0.86 <
< 2.76
A 99% confidence interval for the population standard deviation, σ (0.86 , 2.76)
orchestra answered 2 years agoRelated Solutions
Assume that firm M (the manufacturer) sells an input (a lawn mower) to firm R (the...
Assume that firm M (the manufacturer) sells an input (a lawn
mower) to firm R (the retailer). Now R sells the lawn mower to the
public. R does not incur any cost associated with providing its
retail service (that is, its retail cost is zero). Let X represent
the number of lawn mowers. Assume that M is monopolists, R is
competitive industry, and P is the lawn mower price charged to the
public with the (inverse) demand P=100 – X....
A Company sells two types of lawn mower – the fly-mo and the standard. The selling...
A Company sells two types of lawn mower – the fly-mo and the
standard. The selling price of the Fly-mo is $188 and variable
costs of $152.80. The Standard sells for $180 with the same
variable cost.
Fixed costs are $255,840. The company sells the lawn mowers in
equal proportions (i.e. in the same ratio).
1. What is break-even point in units (number of lawn mowers)?
2. What is break-even point in sales (in US$)?
3. Create a contribution income...
A Company sells two types of lawn mower – the fly-mo and the standard. The selling...
A Company sells two types of lawn mower – the fly-mo and the
standard. The selling price of the Fly-mo is $188 and variable
costs of $152.80. The Standard sells for $180 with the same
variable cost.
Fixed costs are $255,840. The company sells the lawn mowers in
equal proportions (i.e. in the same ratio).
What is break-even point in units (number of lawn mowers)?
What is break-even point in sales (in US$)?
Create a contribution income statement for break-even...
Rewrite the following message refusing the claim for a defective riding lawn mower. The mower was...
Rewrite the following message refusing the claim for a
defective riding lawn mower. The mower was purchased 15 months
earlier. The purchaser has had difficulties with it for some time
and submitted with the claim a statement from a local repair
service verifying the difficulties. The writer’s reason for
refusing is stated in the email.:
Subject: Your May 12 Claim
Mr. Skinner:
Your May 12 claim of defective workmanship in your Model 227
Dandy Klipper riding mower has been reviewed....
Have a standard curve and determine the concentration of the samples. Get the mean, standard deviation...
Have a standard curve and determine the
concentration of the samples. Get the mean, standard deviation for
the two samples tested in triplicate and run a t.test. Is there a
difference between the two samples? These were two different sets
of serum (two different pigs). I would think they will be different
but let's see.
Questions
As you should recall, glucose is a reducing sugar.
There are many chemical assays for reducing sugars such as using
Nelson's alkaline copper reagent...
A)The life expectancy in the United States has a mean of 75 with a standard deviation...
A)The life expectancy in the United States has a mean of 75 with
a standard deviation of 7 years and follows a normal
distribution.
What is the probability of an individual living longer than 80
years?
b)In the two upcoming basketball games, the probability that UTC
will defeat Marshall is 0.63, and the probability that UTC will
defeat Furman is 0.55. The probability that UTC will defeat both
opponents is 0.3465.
What is the probability that UTC will defeat Furman...
A) Determine the sample mean and sample standard deviation. B) Determine the 5-number summary and the...
A) Determine the sample mean and sample standard deviation.
B) Determine the 5-number summary and the IQR of the following
data set. Determine also the outlier/s and the adjacent value/s if
relevant.
30,31,41,23,45,30,37,31,37,26,37,24,42,38
For a population with a normal distribution with mean 23.5 and a standard deviation 2.6, determine...
For a population with a normal distribution with mean 23.5 and a
standard deviation 2.6, determine the following.
(a) About 68% of the population lies between what limits?
(b) About 95% of the population lies between what limits?
(c) About 99.7% of the population lies between what
limits
A dishwasher has a mean life of 12 years with an estimated standard deviation of 1.25...
A dishwasher has a mean life of 12 years with an estimated
standard deviation of 1.25 years ("Appliance life expectancy,"
2013). The life of a dishwasher is normally distributed. Suppose
you are a manufacturer and you take a sample of 10 dishwashers that
you made. a.) TRUE or FALSE: The random variable is defined as the
sum of dishwasher life expectancies in the sample. b.) For a sample
of size 10, state the mean of the sample mean. c.) For...
A dishwasher has a mean life of 10 years with an estimated standard deviation of 1.25...
A dishwasher has a mean life of 10 years with an estimated
standard deviation of 1.25 years ("Appliance life expectancy,"
2013). Assume the life of a dishwasher is normally
distributed.
State the random variable.
Find the probability that a dishwasher will last more than 15
years.
Find the probability that a dishwasher will last less than 6
years.
Find the probability that a dishwasher will last between 8 and
10 years.
If you found a dishwasher that lasted less than...
ADVERTISEMENT
ADVERTISEMENT
Latest Questions
- An investment project costs $20,100 and has annual cash flows of $4,400 for six years. ...
- PUT IN JAVA PROGRAMMING The StockB class: Design a class named StockB that contains the following...
- Draw a DFA for the following ( ∑ = {0,1}): Set of all strings with.
- In the article from Forbes notes that the goal of a leader is not to clone...
- Many people keep time using a 24 hour clock (11 is 11am and 23 is 11pm,...
- UNIX ONLY -- DIFFICULT LAB ASSIGNMENT This is an extremely difficult subject for me. Could you...
- Do you know why your credit card can be refused even though you are profitable?
ADVERTISEMENT