Question

1.Assume that the helium porosity (in percentage) of coal samples taken from any particular seam is normally distributed with true standard deviation σ = 0.8. A sample of 13 specimens from the seam produces average porosity 4.6.

The 90% confidence interval for the true average of helium
porosity is:

(4.316 , 4.884)

(4.235 , 4.965)

(4.205 , 4.995)

Tries 0/2 |

What is the minimum sample size required to estimate the true average porosity within 0.1 with 90% confidence?

694 | 173 | 174 |

2.A random sample of 25 adult females is used to calculate a 95%
confidence interval for the true mean weight of female adults.
Which of the following would reduce the margin of error for the
confidence interval? Choose the best answer.

sample size 20

99% confidence and sample size 20

99% confidence level and sample size 30

sample size 30

99% confidence level

Answer #1

Assume that the helium porosity (in percentage) of coal samples
taken from any particular seam is normally distributed.
How large a sample size is necessary if the width of the 90%
interval is to be .20? Sample standard deviation of .65

As humans we consume food. The body extracts good things such as
proteins and vitamins and throws away waste. A typical waste
product is uric acid. High levels of uric acid can be an indication
of conditions such as gout, kidney disease, and cancer. For females
a high level of uric acid is 6 mg/dL or more and for males a high
level of uric acid is 7 mg/dL or more. Suppose, over a period of
months, an adult female...

A sample of size 30 is taken from the population of morel
mushrooms and used to calculate an average height x ¯ = 4.6
centimeters.. Suppose the sample standard deviation is calculated
to be s =0.5. What is the margin of error for a 90% confidence
interval? Round your answer to 3 decimal places.

The following results are for independent random samples taken
from two populations.
Sample 1
Sample 2
n1 = 20
n2 = 30
x1 = 22.8
x2 = 20.1
s1 = 2.6
s2 = 4.6
(a)
What is the point estimate of the difference between the two
population means? (Use
x1 − x2.
)
(b)
What is the degrees of freedom for the t distribution?
(Round your answer down to the nearest integer.)
(c)
At 95% confidence, what is the margin...

The following results are for independent random samples taken
from two populations.
Sample 1
Sample 2
n1 = 20
n2 = 30
x1 = 22.5
x2 = 20.1
s1 = 2.2
s2 = 4.6
(a)
What is the point estimate of the difference between the two
population means? (Use
x1 − x2.
)
(b)
What is the degrees of freedom for the t distribution?
(Round your answer down to the nearest integer.)
(c)
At 95% confidence, what is the margin...

The following results are for independent random samples taken
from two populations.
Sample 1
Sample 2
n1 = 20
n2 = 30
x1 = 22.5
x2 = 20.1
s1 = 2.9
s2 = 4.6
a) What is the point estimate of the difference between the two
population means? (Use
x1 − x2.)
b) What is the degrees of freedom for the t
distribution? (Round your answer down to the nearest integer.)
c) At 95% confidence, what is the margin of...

1) The weekly oral dose of anabolic steroids was measured on a
sample of 20 body builders. A 95% confidence interval
estimatefortheaverageweeklyoraldoseofanabolicsteroidsobtainedfromtheseresultswas152mgto194
mg. (The margin of error is 21 mg.) Identify which one of the
following interpretations is correct.
a) 95% of all body builders use between 152 mg and 194 mg of
anabolic steroids per week.
b) There is a 0.95 probability that the average weekly dose of
anabolic steroids used by body builders is between
152 mgand194mg.
c)...

1. A sample of 35 circuits from a large normal population has
a mean resistance of 2.35 ohms. We know from past testing that
the
a) population standard deviation is 0.45 ohms. b) population
standard deviation is 0.48 ohms. c) population standard deviation
is 0.43 ohms. d) population standard deviation is 0.46 ohms.
Determine a 95% confidence interval for the true mean
resistance of the population
2. a)Arandomsampleofn=20has x=45ands=8.
b)Arandomsampleofn=22has x=48ands=9.
c)Arandomsampleofn=20has x=45ands=8.
d)Arandomsampleofn=22has x=48ands=9. Form a 95% confidence
interval...

1. For a company whose total number of employees is 100, we
collect data from 7 employees ,5.2, 4.1, 10, 6.8, 3.8, 8.0, and
8.3.
Using these data, write down the upper bound of the 99% CI for
population mean. Assume that these data are from a normal
distribution.
Please provide answer with 2 decimal points.
2. From a sample of size 250, number of females is 173. What is
the point estimate of population proportion?
Provide an answer with...

1. A sample size of n = 70 is drawn from a population with
proportion p = 0.32. Let p̂ be the sample proportion.
Find p̂m and p̂s . Round the standard deviation to four decimal
places.
Find )28.0p̂P ( > .
Find )40.0p̂P ( <
2. On a certain television channel, 20% of the
commercials are local advertisers. A sample of 150 commercials is
selected. Would it be unusual for more than 26% of the commercials
to be local advertisers?...

ADVERTISEMENT

Get Answers For Free

Most questions answered within 1 hours.

ADVERTISEMENT

asked 14 seconds ago

asked 32 minutes ago

asked 33 minutes ago

asked 44 minutes ago

asked 44 minutes ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 2 hours ago

asked 2 hours ago