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
andre [41]
3 years ago
8

The lifetime of lightbulbs that are advertised to last for 4000 hours are normally distributed with a mean of 4250 hours and a s

tandard deviation of 300 hours. What is the probability that a bulb lasts longer than advertised
Mathematics
1 answer:
kobusy [5.1K]3 years ago
6 0

Answer:

79.67% probability that a bulb lasts longer than advertised

Step-by-step explanation:

Problems of normally distributed samples are solved using the z-score formula.

In a set with mean \mu and standard deviation \sigma, the zscore of a measure X is given by:

Z = \frac{X - \mu}{\sigma}

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

In this problem, we have that:

\mu = 4250, \sigma = 300

What is the probability that a bulb lasts longer than advertised?

This is 1 subtracted by the pvalue of Z when X = 4000. So

Z = \frac{X - \mu}{\sigma}

Z = \frac{4000 - 4250}{300}

Z = -0.83

Z = -0.83 has a pvalue of 0.2033

1 - 0.2033 = 0.7967

79.67% probability that a bulb lasts longer than advertised

You might be interested in
What does the slope of the graph of this equation represents ? Y=16,500-1,500x
Levart [38]
Use photo math it works great
4 0
3 years ago
Suppose babies born in a large hospital have a mean weight of 3215 grams, and a variance of 84,681. if 67 babies are sampled at
ziro4ka [17]
The z-score is given by:
z=(x-μ)/σ
but
x-μ=52
thus
z=52/√84681
z=0.1787
Thus:
P(X≤52)=0.9633
7 0
3 years ago
Read 2 more answers
What is 5x-15x + 20y = x + 5<br> Solve for y
Setler79 [48]
Y=11x/20 +.25
<span>Solve for </span><span>y</span><span> by </span>simplifying<span> both sides of the </span>equation<span>, then isolating the </span>variable<span>.</span>
4 0
3 years ago
Read 2 more answers
Math Help:<br><br> Which two answers are correct?
EastWind [94]

Answer:

see below

Step-by-step explanation:

The odd degree (7) tells you the end behaviors are in opposite directions. The negative leading coefficient (-4) tells you the sign of y will be opposite the sign of x.

For x going toward negative infinity, y goes toward positive infinity.

For x going toward positive infinity, y goes toward negative infinity.

6 0
3 years ago
Nellie took a total of 27 quizzes over the course of 3 weeks. After attending 4 weeks of school this quarter, how many quizzes w
Dennis_Churaev [7]

Answer:

The answer is 36

Step-by-step explanation:

If you do 27÷3 you get 9. So if it's 4 weeks you just add 9 which is 36

4 0
3 years ago
Read 2 more answers
Other questions:
  • What is the equation of the line in slope-intercept form the line perpendicular to y=4/9x-6 through (5,-6)
    10·1 answer
  • Which is the range of the function f(x) = 1/7 (9)x
    13·1 answer
  • Which equation shows how many squares there are in all
    8·1 answer
  • The price of a coat is reduced by 15% in a sale.
    13·1 answer
  • Select the best answer for the question
    12·1 answer
  • The perimeter of a square is 54 cm.Find the length of a diagonal, rounding to the nearest tenth
    15·1 answer
  • Mrs. Harris took 6 oranges out of the refrigerator and cut them into wedges, each wedge represents 1/6 of the entire orange. Her
    13·1 answer
  • What is the greatest integer that satisfies the inequality below?
    11·1 answer
  • I want to know organic in grade 10<br>​
    11·1 answer
  • An exam is made of two papers that score differently.
    5·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!