# Question: A company receives lightbulbs from two different suppliers Define the

A company receives lightbulbs from two different suppliers. Define the variables x and y by x = lifetime of a bulb from Supplier 1 y = lifetime of a bulb from Supplier 2 Five hundred bulbs from each supplier are tested, and the lifetime of each bulb (in hours) is recorded. The density histograms in Figure EX7.9 below are constructed from these two sets of observations. Although these histograms are constructed using data from only 500 bulbs, they can be considered approximations to the corresponding population distributions.

a. Which population distribution has the larger mean?

b. Which population distribution has the larger standard deviation?

c. Assuming that the cost of the lightbulbs is the same for both suppliers, which supplier would you recommend? Explain.

d. One of the two distributions pictured has a mean of approximately 1000, and the other has a mean of about 900. What is the approximate mean of the distribution for the variable x (lifetime for a bulb made by Supplier 1)?

e. One of the two distributions pictured has a standard deviation of approximately 100, and the other has a standard deviation of about 175. What is the approximate standard deviation of the distribution for the variable x (lifetime for a bulb made by Supplier 1)?

a. Which population distribution has the larger mean?

b. Which population distribution has the larger standard deviation?

c. Assuming that the cost of the lightbulbs is the same for both suppliers, which supplier would you recommend? Explain.

d. One of the two distributions pictured has a mean of approximately 1000, and the other has a mean of about 900. What is the approximate mean of the distribution for the variable x (lifetime for a bulb made by Supplier 1)?

e. One of the two distributions pictured has a standard deviation of approximately 100, and the other has a standard deviation of about 175. What is the approximate standard deviation of the distribution for the variable x (lifetime for a bulb made by Supplier 1)?

**View Solution:**## Answer to relevant Questions

A random sample is selected from a population with mean m = 100 and standard deviation s = 10. Determine the mean and standard deviation of the x sampling distribution for each of the following sample sizes: a. n 5 9 d. n 5 ...In the library on a university campus, there is a sign in the elevator that indicates a limit of 16 persons. In addition, there is a weight limit of 2500 pounds. Assume that the average weight of students, faculty, and staff ...c. Referring to Part (b), what is the probability that a sample mean will be outside 2 +- 3sx just by chance (that is, when there are no unusual circumstances)? d. Suppose that a machine used to apply the coating is out of ...For each of the following statements, identify the number that appears in boldface type as the value of either a population characteristic or a statistic: a. A department store reports that 84% of all customers who use the ...Suppose that the sampling experiment described in Example 8.1 had used samples of size 10 rather than size 5. If 50 samples of size 10 were selected, the x value for each sample computed, and a density histogram constructed, ...Post your question