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
KIM [24]
3 years ago
6

A sample of 50 drills had a mean lifetime of 12.17 holes drilled when drilling a low-carbon steel. Assume the population standar

d deviation is 6.37.Construct a 95% confidence interval for the mean lifetime of this type of drill
Mathematics
1 answer:
zmey [24]3 years ago
6 0

Using the z-distribution, it is found that the 95% confidence interval for the mean lifetime of this type of drill, in holes drilled, is (10.4, 13.94).

We are given the <u>standard deviation for the population</u>, hence, the z-distribution is used. The parameters for the interval is:

  • Sample mean of \overline{x} = 12.17
  • Population standard deviation of \sigma = 6.37
  • Sample size of n = 50.

The margin of error is:

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

In which z is the critical value.

We have to find the critical value, which is z with a p-value of \frac{1 + \alpha}{2}, in which \alpha is the confidence level.

In this problem, \alpha = 0.95, thus, z with a p-value of \frac{1 + 0.95}{2} = 0.975, which means that it is z = 1.96.

Then:

M = 1.96\frac{6.37}{\sqrt{50}} = 1.77

The confidence interval is the <u>sample mean plus/minutes the margin of error</u>, hence:

\overline{x} - M = 12.17 - 1.77 = 10.4

\overline{x} + M = 12.17 + 1.77 = 13.94

The 95% confidence interval for the mean lifetime of this type of drill, in holes drilled, is (10.4, 13.94).

A similar problem is given at brainly.com/question/22596713

You might be interested in
Circle problem, please help
faust18 [17]
I think that it is A, 180..
5 0
3 years ago
Solve pls brainliest
ahrayia [7]

Answer:

w=2.5

Step-by-step explanation:

divide 12.5 by 5: 12.5/5=2.5, so w=2.5

3 0
2 years ago
Read 2 more answers
100 pts Sam purchased a new car for $17,930. The value of the car depreciated by 19% per year. When he trades the car in after x
erik [133]

Answer: 2500

Step-by-step explanation:

I don’t know if it’s right

4 0
2 years ago
Solve the following similar fraction. 3/4 + 1/4=?​
borishaifa [10]

Answer:

4/4 or 1

Step-by-step explanation:

3/4 (75%) and 1/4 (25%) add them up and you get 1, (100%) or 4/4.

7 0
3 years ago
What's the common difference in −1,−4,−7,−10
kondor19780726 [428]

Answer:

-3

Step-by-step explanation:

7 0
2 years ago
Other questions:
  • Express the fraction in simplest form. 14/16 A.7/16 B. 28/32 C.7/9 D. 7/8. Please help now
    5·2 answers
  • Benjamin is saving money for a new laptop computer . he already has $50 in his account that his grandmother gave him for his bir
    15·1 answer
  • Rose's bank account y = 8x+ 50 what is the rate and what does Y-intercept
    9·1 answer
  • Graph a line that contains the point ( 3 , -6) and has a slope of 1/2
    6·1 answer
  • What is the image point of (-6,-9)(−6,−9) after a translation left 1 unit and down 5 units?
    12·1 answer
  • Brian invests £1500 into his bank account. He receives 2% per year simple interest. How much will Brian have after 3 years? Give
    13·1 answer
  • Can someone help me please? I don't understand this at all
    11·1 answer
  • Which line shows the graph of y = 4x - 5 reflected over the y-axis?
    11·1 answer
  • A snake at the zoo is 4 feet long. A scale model of the snake is 2 inches long. What is the scale factor?
    13·1 answer
  • System of equations, please help.
    14·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!