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
galben [10]
3 years ago
11

The lifetime (in hours) of a 60-watt light bulb is a random variable that has a Normal distribution with σ = 30 hours. A random

sample of 25 bulbs put on test produced a sample mean lifetime of = 1038 hours. If in the study of the lifetime of 60-watt light bulbs it was desired to have a margin of error no larger than 6 hours with 99% confidence, how many randomly selected 60-watt light bulbs should be tested to achieve this result?
Physics
1 answer:
attashe74 [19]3 years ago
5 0

Answer:

They must have about 166 randomly 60 watt light bulbs to achieve the result

N = 166

Explanation:

σ = 30

% 99 = 2.576

Using the standard equation of statistics knowing the difference between the measurement have a margin error no larger than 6 can solve

σ = √∑ ( x - z' )²  / N

Solve to N

N = ( % * σ  / Δ x  ) ²

N = ( 2.576 * 30 / 6 )²

N = 12.88 ²

N = 165. 89 44 ≅ 166

You might be interested in
Chất rắn có tính dị hướng là vật rắn
kari74 [83]

Answer:

Anisotropy, in physics, the quality of exhibiting properties with different values when measured along axes in different directions. Anisotropy is most easily observed in single crystals of solid elements or compounds, in which atoms, ions, or molecules are arranged in regular lattices.

Explanation:

HOPE IT HELPS

6 0
2 years ago
How many electrons are depicted in the electron dot diagram of an electrically neutral nitrogen atom? A. two B. six C. eight D.
goldenfox [79]

Answer is D - five.


<em>Explanation;</em>


- Electron dot diagrams show the valence electrons around the element by using dots.


- Valence electrons are the electrons which are in outermost shell of the atom.


-The atomic number of the N atom is 7.

      Atomic number = number of protons = 7

  If the atom is neutral,

      number of protons = number of electrons.


  Hence, N atom has 7 electrons.


- The electron configuration is 1s² 2s² 2p³.


Hence, N atom has 2 + 3 = 5 valence electrons. So, five electrons are represented in electron dot diagram of N.

4 0
3 years ago
Read 2 more answers
A uniform horizontal rod of mass Mand length rotates with angular velocity about a vertical axis through its center. Attached to
Lostsunrise [7]

Answer:

     o

90

Explanation:

3 0
3 years ago
What kind of symmetry do you have
Keith_Richards [23]
During the daytime, I have mostly line symmetry.

During the night, I often have almost spherical symmetry.
5 0
3 years ago
Read 2 more answers
A jogger travels a route that has two parts. The first is a displacement of 3 km due south, and the second involves a displaceme
spayn [35]

Answer:

a) 2.41 km

b) 38.8°

Questions c and d are illegible.

Explanation:

We can express the displacements as vectors with origin on the point he started (0, 0).

When he traveled south he moved to (-3, 0).

When he moved east he moved to (-3, x)

The magnitude of the total displacement is found with Pythagoras theorem:

d^2 = dx^2 + dy^2

Rearranging:

dy^2 = d^2 - dx^2

dy = \sqrt{d^2 - dx^2}

dy = \sqrt{3.85^2 - 3^2}  = 2.41 km

The angle of the displacement vector is:

cos(a) = dx/d

a = arccos(dx/d)

a = arccos(3/3.85) = 38.8°

7 0
2 years ago
Other questions:
  • __________ force is a fictitious force that some people believe causes you to feel as if you are being pushed outward from the c
    10·2 answers
  • Does specific heat change with mass?
    7·1 answer
  • Rounding<br> What is 13.428 to the nearest tenths positions
    12·1 answer
  • Two blocks can collide in a one-dimensional collision. The block on the left hass a mass of 0.40 kg and is initially moving to t
    6·2 answers
  • Which of the following distances is the longest?a. 0.006 kilometers
    5·1 answer
  • In a rectangular coordinate system a positive point charge q=6.00×10−9 C q=6.00×10−9 C is placed at the point x = +0.150 m, y =
    11·1 answer
  • Which event may occur when ocean salinity increases?
    8·2 answers
  • Công thức dùng tính tần số dao động của con lắc lò xò
    6·1 answer
  • A shell is launched with an initial velocity at an angle of 40.0° above horizontal
    7·1 answer
  • What is a possible state of an object in the absence of a net force?a.)at restb.)constant velocity c.)zero accelerationd.)all of
    9·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!