1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
dolphi86 [110]
3 years ago
8

A supplier of a certain car parts chain of stores wants to estimate the average length of time car owners plan to keep their car

s. From the past it is known that the standard deviation of the length of times car owners plan to keep their cars is 6.5 years. A random sample of 25 car owners results the average length of time of 7.2 years. Calculate and interpret a 99% confidence interval for the average length of time all car owners plan to keep their cars.
Mathematics
1 answer:
____ [38]3 years ago
7 0

Answer:

The 99% confidence interval for the average length of time all car owners plan to keep their cars is between 3.85 years and 10.55 years.

Step-by-step explanation:

We have that to find our \alpha level, that is the subtraction of 1 by the confidence interval divided by 2. So:

\alpha = \frac{1-0.99}{2} = 0.005

Now, we have to find z in the Ztable as such z has a pvalue of 1-\alpha.

So it is z with a pvalue of 1-0.005 = 0.995, so z = 2.575

Now, find the margin of error M as such

M = z*\frac{\sigma}{\sqrt{n}}

In which \sigma is the standard deviation of the population and n is the size of the sample.

M = 2.575*\frac{6.5}{\sqrt{25}} = 3.35

The lower end of the interval is the sample mean subtracted by M. So it is 7.2 - 3.35 = 3.85 years

The upper end of the interval is the sample mean added to M. So it is 7.2 + 3.35 = 10.55 years

The 99% confidence interval for the average length of time all car owners plan to keep their cars is between 3.85 years and 10.55 years.

You might be interested in
Which ratio can<br> form a proportion<br> with 2/3?
Gennadij [26K]

Answer:

6/9

Step-by-step explanation:

7 0
3 years ago
Read 2 more answers
Parallelogram ABCD has the angle measures shown. Can you conclude that it is a rhombus, a rectangle, or a square? Explain.
Nikitich [7]
<span>We can analyze the four optons. 1) Option A. A parallelogram with all four angles of the same measure can be either a square or a rectangle, then this option is not valid. 2) Optrion B. gives not information. 3) A rhombus (a diamond) is a parallelogram with four congruent side (square is a specific case of rhmbus but not all rhombus are squares), and it is enouh to say that one diagonal bisects two interior angles, to conclude that it is a rhombus. 4) If a diagonal creates congruent angles, but you do not know what happens with the opposed angle, you cannot conclude that the parallelogram is a rectangle; it could be a trapezoid with one side perpendicular to the parallel sides. By t his analysis, the answer is option C.</span>
7 0
3 years ago
Read 2 more answers
A store charges 7% sales tax. Which expression can be used to find the total cost of an item with a price of p? 0.07p
Elan Coil [88]

Answer:

a. o.o7p

Step-by-step explanation:

3 1
3 years ago
You have 2/3 of sugar how muck sugar will you use if you makes 6 batches of cookies
zalisa [80]

Answer:

4

Step-by-step explanation:

1 batch = 2/3

so 6 batches = 2/3 * 6

and 2/3 *6 = 4 !

4 0
2 years ago
Three points that are not collinear determine three lines. How many lines are determined by nine points, no three of which are c
Drupady [299]

Answer:

Use the method for solving Bernoulli equations to solve the following differential equation.

StartFraction dy Over dx EndFraction plus StartFraction y Over x minus 9 EndFraction equals 5 (x minus 9 )y Superscript one half

Step-by-step explanation:

Use the method for solving Bernoulli equations to solve the following differential equation.

StartFraction dy Over dx EndFraction plus StartFraction y Over x minus 9 EndFraction equals 5 (x minus 9 )y Superscript one half

4 0
3 years ago
Other questions:
  • Theos kitchen is 192 square feet. a blueprint of his kitchen is created with the scale 1 inch : 4 feet. what is the area of the
    10·1 answer
  • 5 pts<br> Evaluate the following expression, let a = -1, b = 3, and c = 0<br> 10c - lla+4
    10·1 answer
  • Find the least positive angle measurement that is coterminal with 230°.
    7·1 answer
  • 104 tests is what % of 160 tests
    7·1 answer
  • Kerrie is tiling the floor of a kitchen. The kitchen floor measures 11.3 feet by 9.25 feet. She orders enough tiles for 99 squar
    10·2 answers
  • Which is NOT proportionate to 15/45 <br><br> 3/9<br><br> 3/15<br><br> 1/3<br><br> 30/90
    8·1 answer
  • What is this answer 3(4x-5)
    11·1 answer
  • The volume lf a wood with 8m long , 6m wide and 10m height​
    8·2 answers
  • Given two circles whose radii are 5" and 15", the ratio of their areas is
    13·1 answer
  • HELPPPPPPP!!!!!!!!!!!!!
    13·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!