Question

A car manufacturer claims that its cars make on average 30 miles per gallon on a highway. A consumer group tests 25 cars on a highway and finds the average of 27 miles per gallon and a standard deviation of 5.81 miles per gallon. Do these results doubt the claim made by the car manufacturer about the population mean μ? Test the hypotheses H0: μ =30 versus Ha:μ ≠ 30 at 0.05 level of significance.

Suppose that a test of H0: μ =30 versus Ha: μ ≠ 30 at 0.05 level of significance resulted in rejection of the null hypothesis (“reject of H0” may or may not be the correct answer to the previous question). Evaluate the following statement: If a 95% confidence interval for the population mean mu was constructed, it would have contained 30.

A. true

B. unknown

C. false

D. uncertain

E. none of the others

Answer #1

Sample size. =n= 25

A car manufacturer claims that the miles per gallon (mpg) of all
its midsize cars can be modeled with a normal model with N(33,
1.70).
What proportion of cars have miles per gallon less than 31.2
[P(x ≤ 31.2 mpg)]?
What proportion of cars will have miles per gallon greater than
36 [P(x ≥ 36 mpg)]?
What proportion of cars will have miles per gallon greater than
29.7 [P(x ≥ 29.7 mpg)]?
What proportion of cars will have miles per...

An automobile manufacturer claims that its car has a
28.0 miles/gallon (MPG) rating. An independent
testing firm has been contracted to test the MPG for this car since
it is believed that the car has an incorrect manufacturer's MPG
rating. After testing 270 cars, they found a mean
MPG of 27.8. Assume the variance is known
to be 6.25. A level of significance of
0.02 will be used. State the hypotheses.
H0: (BLANK)
Ha: (BLANK)

A car manufacturer claims that the
bumper on its cars is constructed in such a way that if the car is
driven into a wall at a speed of 15 miles per hour the damage to
the car would cost about $200 to fix, on average. A
consumer testing agency wants to check the manufacturer's claim
that average (or mean) expenditure for bumper repair is equal to
$200 against the alternative hypothesis that mean expenditure is
not equal to $200 at...

An automobile manufacturer has given its car a 46.2 miles/gallon
(MPG) rating. An independent testing firm has been contracted to
test the actual MPG for this car since it is believed that the car
has an incorrect manufacturer's MPG rating. After testing 240 cars,
they found a mean MPG of 46.4 . Assume the population variance is
known to be 2.56 . A level of significance of 0.05 will be used.
State the null and alternative hypotheses.

An automobile manufacturer claims that their car has a 33.7
miles/gallon (MPG) rating. An independent testing firm has been
contracted to test the MPG for this car. After testing 12 cars they
found a mean MPG of 34.0 with a variance of 2.56. Is there
sufficient evidence at the 0.05 level that the cars have an
incorrect manufacturer's MPG rating? Assume the population
distribution is approximately normal. Step 4 of 5 : Determine the
decision rule for rejecting the null...

An automobile manufacturer claims that its car has a 28.0
miles/gallon (MPG) rating. An independent testing firm has been
contracted to test the MPG for this car since it is believed that
the car has an incorrect manufacturer's MPG rating. After testing
270 cars, they found a mean MPG of 27.8. Assume the variance is
known to be 6.25 A level of significance of 0.02 will be used. Find
the value of the test statistic. Round your answer to 2...

An automobile manufacturer claims that its car has a 57.7
miles/gallon (MPG) rating. An independent testing firm has been
contracted to test the MPG for this car since it is believed that
the car has an incorrect manufacturer's MPG rating. After testing
210 cars, they found a mean MPG of 57.4. Assume the standard
deviation is known to be 1.9. A level of significance of 0.1 will
be used. Find the value of the test statistic. Round your answer to...

The manufacturer of a new compact car claims the miles per
gallon (mpg) for the gasoline consumption is mound-shaped and
symmetric with a mean of 27.4 mpg and a standard deviation of 10.2
mpg. If 29 such cars are tested, what is the probability the
average mpg achieved by these 29 cars will be greater than 29?
Answer: Round your answer to 4 decimal places as necessary. For
example, 0.1357 would be a legitimate entry. Make sure you include
the...

An automobile manufacturer claims that their car has a 59.1
miles/gallon (MPG) rating. An independent testing firm has been
contracted to test the MPG for this car. After testing 51 cars they
found a mean MPG of 59.3 with a standard deviation of 1.4 MPG. Is
there sufficient evidence at the 0.1 level that the cars have an
incorrect manufacturer's MPG rating? State the null and alternative
hypotheses for the above scenario.

A car manufacturer advertises that its new ‘ultra-green’ car
obtains on average 100 miles per gallon (mpg). A consumer advocacy
group tested a sample of 25 cars. Each car was driven the same
distance in similar conditions, and the following results on mpg
were recorded:
112
111
85
88
99
96
83
87
101
102
113
93
102
92
96
79
117
113
90
78
98
89
99
102
96
Using Descriptive Statistics of Data Analysis of Excel with a...

ADVERTISEMENT

Get Answers For Free

Most questions answered within 1 hours.

ADVERTISEMENT

asked 3 minutes ago

asked 18 minutes ago

asked 21 minutes ago

asked 26 minutes ago

asked 43 minutes ago

asked 57 minutes ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago