Electrical resistors made by a particular factory have a coefficient of variation of 0.28% with a normal distribution of resistances. a) Find the 99% confidence interval for the mean of samples of...

Electrical resistors made by a particular factory have a coefficient of variation of 0.28% with a normal distribution of resistances.

a) Find the 99% confidence interval for the mean of samples of size five if the population mean is 10.00 ohms.

b) How many observations must a sample contain to give at least 99.5% probability that the sample mean is within 0.30% of the population mean?