# Question: A recent study of the life span of portable compact

A recent study of the life span of portable compact disc players found the average to be 3.7 years with a standard deviation of 0.6 year. If a random sample of 32 people who own CD players is selected, find the probability that the mean lifetime of the sample will be less than 3.4 years. If the mean is less than 3.4 years, would you consider that 3.7 years might be incorrect? (6–3)

## Relevant Questions

Of the total population of American households, including older Americans and perhaps some not so old, 17.3% receive retirement income. In a random sample of 120 households, what is the probability that more than 20 ...Using the standard normal distribution, find each probability. (6–1) a. P (0 < z < 2.07) b. P (–1.83 < z < 0) c. P (–1.59 < z < + 2.01) d. P (1.33 < z 1.66) g. P(z < – 2.03) h. P(z > –1.19) i. P(z < 1.93) j. ...What is the difference between a point estimate and an interval estimate of a parameter? Which is better? Why? A study of 415 kindergarten students showed that they have seen on average 5000 hours of television. If the sample standard deviation of the population is 900, find the 95% confidence level of the mean for all students. If a ...a. z a / 2 for the 99% confidence interval b. z a / 2 for the 98% confidence interval c. z a / 2 for the 95% confidence interval d. z a / 2 for the 90% confidence interval e. z a / 2 for the 94% confidence intervalPost your question