Question
In: Statistics and Probability
An electrical firm manufactures light bulbs that have a length of life that is approximately normally...
An electrical firm manufactures light bulbs that have a length of life that is approximately normally distributed with a standard deviation of 40 hours. If a sample of 30 bulbs has a an average life of 780 hours, find a 96% confidence interval for the population mean of all bulbs produced by this firm.
Solutions
Expert Solution
Solution :
Given that,
Point estimate = sample mean = 
=
Population standard deviation = 
=
Sample size = n =
At 96% confidence level the z is ,
= 1 - 96% = 1 - 0.96 = 0.04
/ 2 = 0.04 / 2 = 0.02
Z/2
= Z0.02= 2.05 ( Using z table )
Margin of error = E = Z
/2
* ( 
/
= 2.05 * ( 40/
E= 14.9711
At 96% confidence interval estimate of the population mean
is,
- E < 
<
+ E
780 - 14.9711 <
< 780 + 14.9711
765.0289 <
< 794.9711
( 765.0289 ,794.9711)
orchestra answered 1 year agoRelated Solutions
An electrical firm manufactures light bulbs that have a length of life that is approximately normally...
An electrical firm manufactures light bulbs that have a length
of life that is approximately normally distributed with a standard
deviation of 35 hours. If a sample of 50 bulbs has an average life
of 900 hours, find a 98% confidence interval for the population
mean of all bulbs produced by this firm.A properly labeled
figure of the normal distribution curve and x and/or z values is
required for each problem
An electrical firm manufactures light bulbs that have a length of life that is approximately normally...
An electrical firm manufactures light bulbs that have a length
of life that is approximately normally distributed with a standard
deviation of 40 hours. If a sample of 30 bulbs has an average life
of 780 hours, find a 95% confidence interval for the population
mean of all bulbs produced by this firm.
764.99 < µ < 795.008
768.02 < µ < 791.98
700.30 < µ < 859.70
765.69 < µ < 794.31
An electrical firm manufactures light bulbs that have a length of life that is approximately normally...
An electrical firm manufactures light bulbs that have a length
of life that is approximately normally distributed with an unknown
standard deviation. If a sample of 30 bulbs has an average life of
780 hours and a sample standard deviation of 50 hours, find a 95%
confidence interval for the population mean of all bulbs produced
by this firm.
761.33 < µ < 798.67
764.49 < µ < 795.91
765.07 < µ < 794.93
768.02 < µ < 791.98
An electrical firm manufacturers light bulbs that have a length of life that is approximately normally...
An electrical firm manufacturers light bulbs that have a length
of life that is approximately normally distributed with a standard
deviation of 48 hours. If a sample of 36 bulbs has an average life
of 780 hours, find the bounds of a 99% confidence interval for the
population mean of all bulbs produced by this firm.
780\pm3.29\cdot(8)
None of these
2. An electrical firm manufactures light bulbs that have a lifetime that is approximately normally distributed...
2. An electrical firm manufactures light bulbs that have a
lifetime that is approximately normally distributed with a standard
deviation of 35 hours. A lifetime test of n=25 samples resulted in
the sample average of 1007 hours. Assume the significance level of
0.05.
(a) Test the hypothesis H0:μ=1000
versus H1:μ≠1000 using a
p-value. (6 pts)
(b) Calculate the power of the test if the true mean lifetime is
1010. (8 pts)
(c) What sample size would be required to detect...
A company manufactures light bulbs. These light bulbs have a length of life that is normally...
A company manufactures light bulbs. These light bulbs have a
length of life that is normally distributed with a known standard
deviation of 40 hours. If a sample of 36 light bulbs has an average
life of 780 hours, find the 95 percent confidence interval for the
population mean of all light bulbs manufactured by this
company.
An electrical firm manufacturers batteries that have a length of life that is approximately normally distributed...
An electrical firm manufacturers batteries that have a length of
life that is approximately normally distributed with a standard
deviation of 40 hours. If a sample of 64 batteries has an average
life of 780 hours, find the bounds of a 95% confidence interval for
the population mean of all batteries produced by this firm.
Suppose that the lifetimes of light bulbs are approximately normally distributed, with a mean of 57...
Suppose that the lifetimes of light bulbs are approximately normally distributed, with a mean of 57 hours and a standard deviation of 3.5 hours. With this information, answer the following questions. (a) What proportion of light bulbs will last more than 60 hours? (b) What proportion of light bulbs will last 50 hours or less? (c) What proportion of light bulbs will last between 58 and 61 hours? (d) What is the probability that a randomly selected light bulb lasts less than 46 hours? (a)...
Suppose that the lifetimes of light bulbs are approximately normally distributed, with a mean of 56...
Suppose that the lifetimes of light bulbs are approximately
normally distributed, with a mean of 56 hours and a standard
deviation of 3.3 hours. With this information, answer the
following questions.
(a) What proportion of light bulbs will last more than
61hours?
(b) What proportion of light bulbs will last 51 hours or
less?
(c) What proportion of light bulbs will last between 57 and 62
hours?
(d) What is the probability that a randomly selected light bulb
lasts less...
Suppose that the lifetimes of light bulbs are approximately normally distributed, with a mean of 57...
Suppose that the lifetimes of light bulbs are approximately
normally distributed, with a mean of 57 hours and a standard
deviation of 3.5 hours. With this information, answer the
following questions. (a) What proportion of light bulbs will last
more than 60 hours? (b) What proportion of light bulbs will last
50 hours or less? (c) What proportion of light bulbs will last
between 57 and 61 hours? (d) What is the probability that a
randomly selected light bulb lasts...
ADVERTISEMENT
ADVERTISEMENT
Latest Questions
- Explain the use of neural networking modeling in predictive analytics.
- Current Market Mix of Netflix, as detail as possible, please.
- This is all one question, thank you so much in advance! You must evaluate a proposal...
- X Company is considering the purchase of a new processor that costs $200,000. Shipping and setup...
- There are a large number of tasks involved in information technology and programming, and many of...
- Using one quantitative and one qualitative health policy research method described in this chapter, design a...
- What is the Rawls' solution to the age-old question of social (economic / distributive) justice?...
ADVERTISEMENT