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
natka813 [3]
3 years ago
5

The mean life of a particular brand of light bulb is 1200 hours. if you know that at about 95% of this brand of bulbs will last

between 800 and 1600 hours, then what is the standard deviation of the light bulbs' life?
Mathematics
1 answer:
Snowcat [4.5K]3 years ago
4 0
<span>204
   First, lookup a standard normal table and see what the z-score is for 0.025 (one half of 100% - 95%) to allow for equal sized tails. You should find that the z-score is 1.96. That means that 95% of the time, the value should be within 1.96 standard deviations of the mean. Now let's calculate the standard deviation. 800 is 800 - 1200 = -400 to the left of the mean of 1200. 1600 is 1600 - 1200 = 400 to the right of the mean of 1200. So we are an equal distance of 400 on both sides of the mean. And we know from the z-score of 1.96, that we're 1.96 standard deviations from the mean. So a little division will give us the standard deviation. Which is: 400 / 1.96 = 204.0816327
   So the standard deviation of the light bulbs is 204</span>
You might be interested in
Write the expression in standard form<br> <img src="https://tex.z-dn.net/?f=%5Cfrac%7B7%7D%7B3-15i%7D" id="TexFormula1" title="\
valentina_108 [34]

<em>Answer:</em>

<em>7/78 - 35/78i</em>

<em>Step-by-step explanation:</em>

<em>A complex number is a real number, an imaginary number or a number with both real and imaginary number. Its standard form is: </em>

<em>a + bi </em>

<em> </em>

<em>For the expression, 7/ 3-15i </em>

<em> </em>

<em>(7/ 3-15i) (3+15i) </em>

<em>21 - 105i / (234) </em>

<em>7/78 - 35/78i </em>

4 0
3 years ago
If (X + 8) is a factor of f(x), which of the following must be true?
julsineya [31]

Answer: C

Step-by-step explanation:

If (X + 8) is a factor of f(x), then to find the root, equate the factor to zero. That is,

X + 8 = 0

X = 0 - 8

X = -8

If -8 is substituted into f(x), the equation will tend to zero. That is,

F( -8 ) = 0

C is therefore the correct answer.

4 0
3 years ago
5. Distribute the expression -2(v-10)
mrs_skeptik [129]

Answer: -2v-20

Step-by-step explanation: -2 times v is -2v

and -10 times -2 is -20.

7 0
3 years ago
Read 2 more answers
When will there be 0 pennies in the jar?how did you figured this out?
siniylev [52]
23 3/4 rounds because you can take 95 divided by 4 to get 23 3/4 rounds
6 0
3 years ago
Make a list of. problem solving strategies you have learned in class (example.Draw a picture).
djyliett [7]
Solve a simpler problem
make a table
make a drawing
use a graph
use guess-and-check
solve an equation
8 0
3 years ago
Other questions:
  • What is the order of rotational symmetry for the figure?
    12·1 answer
  • A 25-foot ladder is placed against a building. The bottom of the ladder is 7 feet from the building. If the top of the ladder sl
    9·1 answer
  • Money off coupons has been circulated to 300 house holds.only 2/5m of these were redeemed (used) in the local supermarket to get
    14·1 answer
  • The set of possible values of m is {5,7,9}. What is the set of possible values of k if 2k=m+3?
    5·1 answer
  • doris tiene en su cartera billetes de $10 y de $20.si en total tienen 25 billetes y $330 ¿cuantos billetes tiene cada uno?
    10·2 answers
  • The speedometer in Kevin's car reads in both miles/hour and kilometers/hour. What information is needed to convert between these
    10·1 answer
  • During Marta's last youth league soccer game, the starting players for each team had varied heights. The following is a list of
    5·1 answer
  • If triangle RST is within Quadrant 4 and cos R= √3/2, what is the value of cotR
    13·1 answer
  • Find the value of the variable.
    15·1 answer
  • Question is in picture<br><br> Drag and drop the steps in order to correctly complete the proof
    10·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!