stat

A company installs 5000 light bulbs, each with an average life of 500 hours, standard deviation of 100 hours, and
distribution approximated by a normal curve. Find the percentage of bulbs that can be expected to last the period of
time.
77) At least 500 hours

  1. 👍
  2. 👎
  3. 👁
  1. A normal distribution is symmetrical about the mean, which means that 50% of the cases are above the mean, and 50%, below.

    So how many % of the lightbulbs will last at least 500 hours?

    1. 👍
    2. 👎

Respond to this Question

First Name

Your Response

Similar Questions

  1. business statitics

    a) The mean lifetime of a sample of 100 light tubes produced by a company is found to be 1570 hours with standard deviation of 80 hours. Test the hypothesis that the mean lifetime of the tubes produced by the company is 1600 hrs.

  2. 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

  3. statistics

    the life of light bulbs is distributed normally. The variance of the life time is 225 and the mean lifetime of a bulb is 590 hours. Find the probability of a bulb lasting for at most 603 hours. Yeah, WTF??? Why me!??!

  4. Statistics

    An electrical firm which manufactures a certain type of bulb wants to estimate its mean life. Assuming that the life of the light bulb is normally distributed and that the standard deviation is known to be 40 hours, how many bulbs

  1. Math

    Daphne replaced light bulbs in her mothers store.She had 3/4 of a box of light bulbs. She used 1/3 of the bulbs. a. What fraction of the box of light bulbs was left? b. How many light bulbs are in a full box? Explain. Thanks to

  2. Math (Statistics)

    PLEASE GET BACK TO ME ASAP!! 1) Use the given data to find the minimum sample size required to estimate the population proportion. Margin of error: 0.04; confidence level: 94%; q̂ unknown a. 486 *** b. 572 c. 553 d. 587 2) Use

  3. Statistics

    A certain type of lightbulb is advertised to have an average lifetime of 1,000 hours. Assume the lifetimes of these lightbulbs are approximately normally distributed with a standard deviation of 250 hours. A) Find the percentage

  4. Statistics

    A purchasing agent for a trucking company is shopping for replacement tires for their trucks from two suppliers. The suppliers' prices are the same. However, Supplier A's tires have an average life of 60,000 miles with a standard

  1. Statistics

    The mean life expectancy of a certain type of light bulb is 945 hours with a standard deviation of 21 hours. What is the approximate standard deviation of the sampling distribution of the mean for all samples with n=50?

  2. 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

  3. Probability and Statistics

    For questions 1- 5 use confidence intervals to test the hypothesis. 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

  4. statisitics

    A company installs 5000 light bulbs, each with an average life of 500 hours, standard deviation of 100 hours, and distribution approximated by a normal curve. How many bulbs should have a life expectancy between 400 and 600 hours?

You can view more similar questions or ask a new question.