Question

Suppose we model light bulb lifetimes as having normal distribution with mean and standard deviation 500...

Suppose we model light bulb lifetimes as having normal distribution with mean and standard deviation 500 and 50 hours, respectively.

Find the value of d such that 30% of all light bulbs have lifetime more than d.

0 0
Add a comment Improve this question Transcribed image text
Answer #1

as top 30% will fall at 70th percentile:

for 70th percentile critical value of z= 0.52
therefore corresponding value d=mean+z*std deviation= 526.00 hours
Add a comment
Know the answer?
Add Answer to:
Suppose we model light bulb lifetimes as having normal distribution with mean and standard deviation 500...
Your Answer:

Post as a guest

Your Name:

What's your source?

Earn Coins

Coins can be redeemed for fabulous gifts.

Not the answer you're looking for? Ask your own homework help question. Our experts will answer your question WITHIN MINUTES for Free.
Similar Homework Help Questions
  • A light bulb manufacturer wants to compare the mean lifetimes of two of its light bulbs,...

    A light bulb manufacturer wants to compare the mean lifetimes of two of its light bulbs, model A and model B. Independent random samples of the two models were taken. Analysis of 11 bulbs of model A showed a mean lifetime of 1345 hours and a standard deviation of 102 hours. Analysis of 15 bulbs of model B showed a mean lifetime of 1389 hours and a standard deviation of 82 hours. Assume that the populations of lifetimes for each...

  • please answer neatly and correctly! light bulb manufacturer wants to compare the mean lifetimes of two...

    please answer neatly and correctly! light bulb manufacturer wants to compare the mean lifetimes of two of its light bulbs, model A and model B. Independent random samples of the two models were taken. Analysis of 9 bulbs of model A showed a mean lifetime of 1234 hours and a standard deviation of 81 hours. Analysis of 15 bulbs of model B showed a mean lifetime of 1391 hours and a standard deviation of 110 hours. Assume that the populations...

  • Please answer neatly and correctly! A light bulb manufacturer wants to compare the mean lifetimes of...

    Please answer neatly and correctly! A light bulb manufacturer wants to compare the mean lifetimes of two of its light bulbs, model A and model B. Independent random samples of the two models were taken. Analysis of 15 bulbs of model A showed a mean lifetime of 1350 hours and a standard deviation of 102 hours. Analysis of 14 bulbs of model B showed a mean lifetime of 1384 hours and a standard deviation of 91 hours. Assume that the...

  • Suppose that the lifetimes of light bulbs are approximately normally distributed, with a mean of 57...

    Suppose that the lifetimes of light bulbs are approximately normally distributed, with a mean of 57 hours and a standard deviation of 3.5 hours. With this information, answer the following questions. (a) What proportion of light bulbs will last more than 61 hours? (b) What proportion of light bulbs will last 52 hours or less? (c) What proportion of light bulbs will last between 57 and 61 hours? (d) What is the probability that a randomly selected light bulb lasts...

  • answer a-f, clearly show the steps thanks 1. . The lifetimes of light bulbs produced by...

    answer a-f, clearly show the steps thanks 1. . The lifetimes of light bulbs produced by a particular manufacturer have mean 1,200 hours and standard deviation 400 hours, The population distribution is normal. Suppose that you purchase 16 bulbs, which can be regarded as a random sample from the' manufacturer's output. a)What is the mean of the sample mean lifetime? Explain. bWhat is the standard error of the sample mean? Explain. c)What is the probability that, on average, these 16...

  • Suppose that the lifetimes of light bulbs are approximately normally distributed, with a mean of 57...

    Suppose that the lifetimes of light bulbs are approximately normally distributed, with a mean of 57 hours and a standard deviation of 3.5 hours. With this information answer the following questions. (a) What proportion of light bulbs will last more than 62 hours? (b) What proportion of light bulbs will last 50 hours or less? (c) What proportion of light bulbs will last between 58 and 62 hours? (d) What is the probability that a randomly selected light bulb lasts...

  • Suppose the manufacturer claims that the mean lifetime of a light bulb is more than 10,000...

    Suppose the manufacturer claims that the mean lifetime of a light bulb is more than 10,000 hours. In a sample of 30 light bulbs, it was found that they only last 9,900 hours on average. Assume the population standard deviation is 120 hours. At 0.05 significance level, can we reject the claim by the manufacturer? Select one: a. We reject the claim b. We accept the claim

  • Can anyone help? Suppose that the lifetimes of light bulbs are approximately normally​ distributed, with a...

    Can anyone help? Suppose that the lifetimes of light bulbs are approximately normally​ distributed, with a mean of 56 hours and a standard deviation of 3.2 hours. With this​ information, answer the following questions. ​(a) What proportion of light bulbs will last more than 62 ​hours? ​ (b) What proportion of light bulbs will last 50 hours or​ less? ​(c) What proportion of light bulbs will last between 59 and 62 ​hours? ​ (d) What is the probability that a...

  • Suppose that the lifetimes of light bulbs are approximately normally distributed, with a mean of 57...

    Suppose that the lifetimes of light bulbs are approximately normally distributed, with a mean of 57 hours and a standard deviation of 3.5 hours. With this information, answer the following questions. (a) What proportion of light bulbs will last more than 61 hours? (b) What proportion of light bulbs will last 51 hours or less? (c) What proportion of light bulbs will last between 59 and 61 hours? (d) What is the probability that a randomly selected light bulb lasts...

  • Suppose that the lifetimes of light bulbs are approximately normally​ distributed, with a mean of 56...

    Suppose that the lifetimes of light bulbs are approximately normally​ distributed, with a mean of 56 hours and a standard deviation of 3.3 hours. The proportion of light bulbs that last 50 hours or less is ?

ADVERTISEMENT
Free Homework Help App
Download From Google Play
Scan Your Homework
to Get Instant Free Answers
Need Online Homework Help?
Ask a Question
Get Answers For Free
Most questions answered within 3 hours.
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT