QUESTION
i. What is the difference between point estimation and interval estimation?
ii. A sample of 8 observations has been taken from a population in which the random variable is normally distributed. The sample mean is 25 and the sample standard deviation is 5. Determine a 95% confidence interval for the population mean.
iii. The mean life of a sample of 200 light tubes produced by a company is found to be 3160 hours with a standard deviation of 180 hours. Test the hypothesis that the mean lifetime of the tubes by the company is 3200 hours.
iv. A sample of 20 measurements of the diameter of a sphere gave a mean 4.38 inches and standard deviation of 0.06 inches find
a) 95% confidence limit to the actual diameter.
b) 99% confidence limit to the actual diameter.