statistics

2. The new Twinkle bulb has a standard deviation hours. A random sample of 77 light bulbs is selected from inventory. The sample mean was found to be 492 hours.
a. Find the margin of error E for a 90% confidence interval.
Round your answer to the nearest hundredths.

  1. 👍
  2. 👎
  3. 👁
  1. Margin of error = z-value (sd/√n)

    Find the z-value corresponding to 90% confidence using a z-table.

    sd = standard deviation
    n = sample size

    I hope this will help get you started.

    1. 👍
    2. 👎
  2. Please someone help me? The new twinkle bulb has a standard deviation 35 hours. A random sample of 50 light bulbs is selected from inventory. The sample mean was found to be x=500 hrs. Find the margin of error for 95%, construct a 95% confidence interval for the mean life of all Twinkle bulbs. I am desperate.

    1. 👍
    2. 👎

Respond to this Question

First Name

Your Response

Similar Questions

  1. 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

  2. statistics

    what are the mean and standard deviation of a sampling distribution consisting of samples of size 16? these sameples were drawn from a population whose mean is 25 and who standard deviation is 5. a. 25 and 1.25 b. 5 and 5 c. 25

  3. Math (Statistic)

    Considered the sampling distribution of a sample mean obtained by random sampling from an infinite population. This population has a distribution that is highly skewed toward the larger values. a) How is the mean of the sampling

  4. algebra

    The light intensity of a light bulb varies inversely as the square of the distance from the light bulb. The function I(d) = k/d^2 models this situation, where I is the light intensity, d is the distance from a light source, and k

  1. 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

  2. statistics

    The mean lifetime of a sample of 100 light tubes is 1570 hours with a standard deviation of 80 hours test the hypothesis that the mean lifetime of the tubes is 1600 hours

  3. 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

  4. 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?

  1. Business Statistics

    The quality control manager at a light bulb factory needs to estimate the mean life of a large shipment of light bulbs. The manufacturer's specifications are that the standard deviations is 100 hours. A random sample of 64 light

  2. 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

  3. Statistics

    For the manufacturing plant discussed in Exercise 8.10, the union president and the human resources director jointly select a simple random sample of 36 employees to engage in a discussion with regard to the company’s work rules

  4. Statistics

    1) Let z be a normal random variable with mean 0 and standard deviation 1. The 4th decile of z is ___. a) 0.67 b) –1.25 c) -0.25 d) 1.28 e) 0.50 2) According to the central limit theorem, if a sample of size 50 is drawn from a

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