(19) Let x represents the life of a light bulb. The x distribution has a mean...
The quality control manager at a light bulb factory needs to estimate the mean life of a large shipment of light bulbs. The standard deviation is 92 hours. A random sample of 64 light bulbs indicated a sample mean life of 360 hours. Complete parts (a) through (d) below. that the lightbulbs have a mean life of 410 hours. c. Must you assume that the population light bulb life is normally distributed? Explain. O A. Yes, the sample size is...
The mean life of a particular brand of light bulb is 1200 hours and the standard deviation is 75 hours. Tests show that the life of the bulb is approximately normally distributed. What is the range of hours that approximately 68% of the bulbs will last?
A light bulb manufacturer claims that the mean life of a certain type of light bulb is 750 hours. If a random sample of 36 light bulbs has a mean life of 725 hours with a standard deviation of 60 hours. Use a=0.05a. State the null and alternative hypotheses.b. State the Type I and Type II errors.c. Find the critical value. Do you have enough evidence to reject the manufacturer’s claim?d. Find the p-value.e. Construct a 95% confidence interval for...
A light bulb (the lifetime is assumed to follow an exponential distribution) has a mean life of 400 hours. What is the probability of the bulb lasting 1) less than 300 hours; 2) more than 500 hours; 3) between 200 and 500 hours?
The life in hours of a 75-watt light bulb is known to be normally distributed with σ = 27 hours. A random sample of 20 bulbs has a mean life of x Overscript bar EndScripts = 1015 hours. Suppose that we wanted the total width of the two-sided confidence interval on mean life to be six hours at 95% confidence. What sample size should be used? Round up the answer to the nearest integer.
A light bulb manufacturer guarantees that the mean life of a certain type of light bulb is at least 775 hours. A random sample of 23 light bulbs has a mean life of 763 hours. Assume the population is normally distributed and the population standard deviation is 64 hours. At alpha equals 0.08, do you have enough evidence to reject the manufacturer's claim? Complete parts (b) through (d) (b) Identify the critical value(s). Use technology. (c) Identify the standardized test...
a) The life hours of a 75-watt light bulb is known to be approximately normally distributed with standard deviation 25 hours. A random sample of 25 bulbs has a mean life of x 1050 hours.Construct the 95% confidence interval for mean life, .
The quality control manager at a light bulb factory needs to estimate the mean life of a large shipment of light bulbs. The standard deviation is 98 hours. A random sample of 49 light bulbs indicated a sample mean life of 300 hours. (a) Construct a 99% confidence interval estimate for the population mean life of light bulbs in this shipment. The 99% confidence interval estimate is from a lower limit of 263.9 hours to an upper limit of 336.1...
Let X be the length of life of a 60-watt light bulb manufactured by a certain company. If a random sample of 25 units is tested until they burn out, yielding a sample mean of x = 1478 hours and s 2 x = 1296, compute a confidence 95 % -confidence interval for the mean and the variance.
The life in hours of a 75-watt light bulb is known to be normally distributed with σ = 25 hours. Suppose that you wanted the total width of the two-sided confidence interval on the mean life to be six hours at 95% confidence. What sample size should be used?