Probability Statistics

posted by .

a manufacturing plant uses 3000 light bulbs whose lifetimes are independently normally distributed with mean 500 hrs, and standard deviation 50 hrs. to minimize the number of bulbs that burn out during production hours, all bulbs are replaced after given period of operation. how often should the bulbs be replaced if you want no more than 1% to burn out between replacements?

Should I just look up 1% under the z-distribution and find corresponding z-score to it, and with that find the X-value in hours?

  • Probability Statistics -

    Yes.

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. probability and statistics

    An electrical firm manufactures light bulbs that have a usuable life that is normally distributed with a mean of 1000 hours and a standard deviation of 80 hours. Find the probability that a package of 4 bulbs would last at least 4400 …
  4. Statistics 1

    If light bulbs are normally distributed with a mean of 2500 hrs. and a standard deviation of 500 hrs. what percentage of light bulbs have a life span less than 2500 hrs.?
  5. 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?
  6. Ashworth college

    The lifetimes of light bulbs of a particular type are normally distributed with a mean of 270 hours and a standard deviation of 11 hours. What percentage of the bulbs has lifetimes that lie within 2 standard deviations of the mean …
  7. Statistics

    The lifetimes of projector bulbs of a particular type are normally distributed with a mean of 470 hours and a standard deviation of 15 hours. What percentage of the bulbs has lifetimes that lie within 2 standard deviations of the mean …
  8. Statistics

    The lifetimes of projector bulbs of a particular type are normally distributed with a mean of 470 hours and a standard deviation of 15 hours. What percentage of the bulbs has lifetimes that lie within 2 standard deviations of the mean …
  9. statistics

    The lifetimes of light bulbs of a particular type are normally distributed with a mean of 370 hours and a standard deviation of 5 hours. What percentage of bulbs has lifetimes that lie within 1 standard deviation of the mean on either …
  10. math

    2) The lifetimes of light bulbs of a particular type are normally distributed with a mean of 370 hours and a standard deviation of 5 hours. What percentage of bulbs has lifetimes that lie within 1 standard deviation of the mean on …

More Similar Questions