statistics

posted by .

Solve the problem. The lifetime of a new brand of light bulb can be described by a Normal model with a mean of 2000 hours and a standard deviation of 250 hours. Find the percentage of light bulbs that will last more than 2600 hours.

A.) 100%
B.) 5%
C.) 99.18%
D.) 0.82%
E.) Cannot be determined

  • statistics -

    Z = (score-mean)/SD

    Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion related to that Z score.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Math

    A consumer buys n light bulbs, each of which has a lifetime that has a mean of 800 hours, a standard deviation of 100 hours, and a normal distribution. A light bulb is replaced by another as soon as it burns out. Assuming independence …
  2. Math

    A consumer buys n light bulbs, each of which has a lifetime that has a mean of 800 hours, a standard deviation of 100 hours, and a normal distribution. A light bulb is replaced by another as soon as it burns out. Assuming independence …
  3. statistics

    A new extended-life light bulb has an average service life of 750 hours, with a standard deviation of 50 hours. If the service life of these light bulbs approximates a normal distribution, about what percent of the distribution will …
  4. math

    1) A light bulb producing company states that its lights will last an average of 1200 hours with a standard deviation of 200 hours. A sample of 100 light bulbs from the company were tested and the researcher found that the average …
  5. Statistics

    Can anyone tell me how to use TI-84 calculator to solve this problem?
  6. Statistics

    A company has developed a new type of light bulb, and wants to estimate its mean lifetime. A simple random sample of 12 bulbs had a sample mean lifetime of 692 hours with a sample standard deviation of 30 hours. It is reasonable to …
  7. sTATISTICS

    If light bulbs have lives that are normally distributed with a mean of 2500 hours and a standard deviation of 500 hours, approximately what percentage of light bulbs has a life of more than 3000 hours?
  8. Statistics

    If light bulbs have lives that are normally distributed with a mean of 2500 hours and a standard deviation of 500 hours, what percentage of light bulbs have a life less than 2500 hours
  9. Math

    If light bulbs have lives that are normally distributed with a mean of 2500 hours and a standard deviation of 500 hours, use the 68-95-99.7 rule to approximate the percentage of light bulbs having a life between 2000 hours and 3500 …
  10. Math ---HELP!!!!!

    light bulbs have lives that are normally distributed with a mean of 2500 hours and a standard deviation of 500 hours, use the 68-95-99.7 rule to approximate the percentage of light bulbs having a life between 2000 hours and 3500 hours?

More Similar Questions