Question

The quality control manager at a light bulb factory needs to estimate the mean life of a large shipment of light bulbs. The standard deviation is 98 hours. A random sample of 49 light bulbs indicated a sample mean life of 300 hours.

Suppose the standard deviation changes to 77 hours. What are your answers in (a) and (b)?

(Ans.) The 99% confidence interval estimate would be from a lower limit of 271.7 hours to an upper limit of 328.3 hours.

Based on the sample data and a standard deviation of 77 hours,
the manufacturer **(does not have / has)-(which one)**
the right to state that the lightbulbs have a mean life of 350
hours. A mean of 350 hours is **(less than 2 / more than
4)-(which one)** standard errors **(above /
below)-(which one)** the sample mean, so it is
**(highly unlikely / likely)-(which one)** that the
lightbulbs have a mean life of 350 hours.

Answer #1

z value at 99% = 2.576

CI = mean +/- z *(s/sqrt(n))

= 300 +/- 2.576 *(98/sqrt(49))

= (263.9 , 336.1 )

Lower limit = 263.9

Upper limit = 336.1

b)

mean = 300 , sd = 98

3 *sd = 3 * 98 = 294

350 > 294

the manufacturer does not have the right to state that the
lightbulbs have a mean life of 350 hours.

c)

sd = 77

z value at 99% = 2.576

CI = mean +/- z *(s/sqrt(n))

= 300 +/- 2.576 *(77/sqrt(49))

= (271.7 , 328.3)

Lower limit = 271.7

Upper limit = 328.3

The 99% CI is 271.7 to 328.3 hours

Based on the sample data, the manufacturer **does not
have** the right to state that the lightbulbs have a mean
life of 350 hours. A mean of 350 hours is * more
than 3* standard errors

The quality control manager at a light bulb factory needs to
estimate the mean life of a large shipment of light bulbs. The
standard deviation is 98 hours. A random sample of 49 light bulbs
indicated a sample mean life of 300 hours.
(a) Construct a 99% confidence interval estimate for the
population mean life of light bulbs in this shipment.
(Ans.) The 99% confidence interval estimate is from a lower
limit of 263.9 hours to an upper limit of...

The quality control manager at a light bulb factory needs to
estimate the mean life of a large shipment of light bulbs. The
standard deviation is 91 hours. A random sample of 49 light bulbs
indicated a sample mean life of 290 hours. Complete parts (a)
through (d) below.
A. Construct a 99% confidence interval estimate for the
population mean life of light bulbs in this shipment. The 99%
confidence interval estimate is from a lower limit of [ ]...

The quality control manager at a light bulb factory needs to
estimate the mean life of a large shipment of light bulbs. The
standard deviation is
7878
hours. A random sample of
3636
light bulbs indicated a sample mean life of
280280
hours. Complete parts (a) through (d) below.
a. Construct a
9595%
confidence interval estimate for the population mean life of
light bulbs in this shipment.The
9595%
confidence interval estimate is from a lower limit of
254.5254.5
hours to...

The quality control manager at a light bulb factory needs to
estimate the mean life of a large shipment of light bulbs. The
standard deviation is 104 hours. A random sample of 64 light bulbs
indicated a sample mean life of 390 hours. Complete parts (a)
through (d) below.
Construct a 99 % confidence interval estimate for the population
mean life of light bulbs in this shipment.
c. Must you assume that the population light bulb life is
normally distributed?...

The quality control manager at a light-bulb factory needs to
estimate the mean life of a new type of light-bulb. The population
standard deviation is assumed to be 65 hours. A random sample of 40
light-bulbs shows a sample mean life of 505 hours. Construct and
explain a 95% confidence interval estimate of the population mean
life of the new light-bulb.
what size sample would be needed to achieve a margin of error of
15 hours or less?

The quality control manager at a light-bulb factory
needs to estimate the mean life of a new type of light-bulb. The
population standard deviation is assumed to be 50 hours. A random
sample of 35 light-bulbs shows a sample mean life of 490 hours.
Construct and explain a 90% confidence interval estimate of the
population mean life of the new light-bulb. What size sample would
be needed to achieve a margin of error of 15 hours or less? Show
all...

1. The quality control manager at a light-bulb factory needs to
estimate the mean life of a new type of light-bulb. The population
standard deviation is assumed to be 45 hours. A random sample of 37
light-bulbs shows a sample mean life of 470 hours. Construct and
explain a 99% confidence interval estimate of the population mean
life of the new light-bulb.

The quality-control manager at a compact fluorescent light
bulb (CFL) factory needs to determine whether the mean life of a
large shipment of CFLs is equal to 7540 hours. The population
standard deviation is 735 hours. A random sample of 49 light bulbs
indicates a sample mean life of 7,288 hours.
Construct a 95% confidence interval estimate of the population
mean life of the light bulbs?
___ <= MU <= ___ (Round to the nearest whole number as
needed.)

The
operations manager at a compact fluorescent light bulb (CFL)
factory needs to estimate the mean life of a large shipment of
CFLs. The manufacturer’s specifications are that the standard
deviation is 1,000 hours. A random sample of 64 CFLs indicated a
sample mean life of 7,500 hours.
a.
Construct a 95% confidence interval estimate for the population
mean life of compact fluorescent light bulbs in this
shipment.
b. Do
you think that the manufacturer has the right to state...

the quality control manager at a compact fluorescent light bulb
factory needs to determine whether the mean life of a large
shipment of CFLs is equal to 7506 hours. the population standard
deviation is 900 hours. a random sample of 81 light bulbs indicates
a sample mean life of 7256 hours
A at the 0.05 level of significance, is there evidence that the
mean life is different from 7506 hours
B compute the p value and interpret its meaning
C...

ADVERTISEMENT

Get Answers For Free

Most questions answered within 1 hours.

ADVERTISEMENT

asked 1 minute ago

asked 10 minutes ago

asked 10 minutes ago

asked 18 minutes ago

asked 28 minutes ago

asked 45 minutes ago

asked 51 minutes ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago