# Question: A popular flashlight that uses two D size batteries was selected

A popular flashlight that uses two D-size batteries was selected, and several of the same models were purchased to test the “continuous-use life” of D batteries.As fresh batteries were installed, each flashlight was turned on and the time noted.When the flashlight no longer produced light, the time was again noted.The resulting “life” data from Rayovac batteries had a mean of 21.0 hours. Source: http://www.rayovac.com. Assume these values have a normal distribution with a standard deviation of 1.38 hours.

a. What is the probability that one randomly selected Rayovac battery will have a test life of between 20.5 and 21.5 hours?

b. What is the probability that a randomly selected sample of 4 Rayovac batteries will have a mean test life of between 20.5 and 21.5 hours?

c. What is the probability that a randomly selected sample of 16 Rayovac batteries will have a mean test life of between 20.5 and 21.5 hours?

d. What is the probability that a randomly selected sample of 64 Rayovac batteries will have a mean test life of between 20.5 and 21.5 hours?

e. Describe the effect that the increase in sample size had on the answers for parts b–d

a. What is the probability that one randomly selected Rayovac battery will have a test life of between 20.5 and 21.5 hours?

b. What is the probability that a randomly selected sample of 4 Rayovac batteries will have a mean test life of between 20.5 and 21.5 hours?

c. What is the probability that a randomly selected sample of 16 Rayovac batteries will have a mean test life of between 20.5 and 21.5 hours?

d. What is the probability that a randomly selected sample of 64 Rayovac batteries will have a mean test life of between 20.5 and 21.5 hours?

e. Describe the effect that the increase in sample size had on the answers for parts b–d

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

c. How many of the sample means in part b have values between 4 and 6? What percentage is that? d. Compare the answers to parts a and c, and explain any differences that occurred. a. What is a sampling distribution of sample means? b. A sample of size 3 is taken from a population, and the sample mean is found. Describe how this sample mean is related to the sampling distribution of sample means. A report in The Washington Post (April 26, 2009) stated that the average age for men to marry in the United States is now 28 years of age. If the standard deviation is assumed to be 3.2 years, find the probability that a ...Let’s simulate the sampling distribution related to the disc jockey’s concern for “length of cut” in Exercise 7. 62. a. Use a computer to randomly generate 50 samples, each of size 10, from a normal distribution ...a. Click “10” for “# of samples.” Note the sample means and the probability of their being less than 1451 if the true mean is really 1500. b. Change to “Batch” and simulate 1000 more samples. What is the ...Post your question