Question

A consumer organization wants to estimate the actual tread wear index of a brand name of tires that claims "graded 250" on the sidewall of the tire. A random sample of n equals 15 indicates a sample mean tread wear index of 242.9 and a sample standard deviation of 18.3. Complete parts (a) through (c).

A. Assuming that the population of tread wear indexes is normally distributed, construct a 95 % confidence interval estimate of the population mean tread wear index for tires produced by this manufacturer under this brand name.

B.Assuming that the population of tread wear indexes is normally distributed, construct a 95 % confidence interval estimate of the population mean tread wear index for tires produced by this manufacturer under this brand name.

a. No, because a grade of 250 is not in the interval.

b. Yes, because a grade of 250 is in the interval.

c. Yes comma because a grade of 250 is not in the interval.

d. No comma because a grade of 250 is in the interval.

C.Explain why an observed tread wear index of 254 for a particular tire is not unusual, even though it is outside the confidence interval developed in (a).

a. It is not unusual because it is only 0.61 standard deviations above the sample mean.

b. It is not unusual because it is only 0.05 standard deviations above the confidence interval.

c. It is not unusual because it is actually in the confidence interval.

d. It is not unusual because it is just outside the confidence interval.

Answer #1

A consumer organization wants to estimate the actual tread wear
index of a brand name of tires that claims "graded 250" on the
sidewall of the tire. A random sample of n equals n=25 indicates a
sample mean tread wear index of 237.3 and a sample standard
deviation of 27.6 Complete parts (a) through (c).
a.
Assuming that the population of tread wear indexes is normally
distributed, construct a 99 % confidence interval estimate of the
population mean tread wear...

A consumer organization wants to estimate the actual tread wear
index of a brand name of tires that claims "graded
150" on the sidewall of the tire. A random sample of n=21
indicates a sample mean tread wear index of 137.3
and a sample standard deviation of 24.3.
a.a.
Assuming that the population of tread wear indexes is normally
distributed, construct a 90%
confidence interval estimate of the population mean tread wear
index for tires produced by this manufacturer under...

A consumer organization wants to estimate the actual tread wear
index of a brand name of tires that claims "graded 200"
on the sidewall of the tire. A random sample of n=20 indicates a
sample mean tread wear index of 196.6. and a sample standard
deviation of 29.7.
Complete parts (a)
.
Assuming that the population of tread wear indexes is normally
distributed, construct a 95% confidence interval estimate of the
population mean tread wear index for tires produced by...

A consumer organization wants to estimate the actual tread wear
index of a brand name of tires that claims "graded
200 on the sidewall of the tire. A random sample ofn equals
18indicates a sample mean tread wear index of192.5
and a sample standard deviation of22.7
Complete parts (a) through (c).
a.a.
Assuming that the population of tread wear indexes is normally
distributed, construct a90 %
confidence interval estimate of the population mean tread wear
index for tires produced by...

A consumer organization wants to estimate the actual treadwear
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A tire manufacturer is interested in testing the fuel economy
for two different tread patterns. Tires of each tread type are
driven for 1000 miles on each of 18 different cars. In a separate
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A manufacturer claims that the life span of its tires is
52 comma 00052,000
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100100
tires at random and test them. The mean life span is
51 comma 79951,799
miles. Assume
sigma?equals=700700.
Complete parts? (a) through? (c).
?(a) Assuming the? manufacturer's claim is? correct, what is the
probability that the mean of the sample...

A manufacturer claims that the life span of its tires is 52
comma 000 miles. You work for a consumer protection agency and you
are testing these tires. Assume the life spans of the tires are
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The mean life span is 51 comma 729 miles. Assume sigmaequals900.
Complete parts (a) through (c). (a) Assuming the manufacturer's
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The sample size ne

A researcher is interested in evaluating a certain brand of
radial auto tire. Twenty tires are randomly selected from retail
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is no tread left. The number of miles (in thousands) were as
follows:...

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