Question

A set of metal bars are known to have a mean diameter of 9.15mm with a standard deviation of 0.18mm. If it can be assumed that the diameters are normally distributed, find the 75% ans 95% confidence levels for an individual bar.

The mean value of batteries produced by a company is 3.72 volts, with a standard deviation of 0.12 volts. Find the 95% confidence limit of 10 batteries, chosen at random, and connected in seriesThe mean value of batteries produced by a company is 3.72 volts, with a standard deviation of 0.12 volts. Find the 95% confidence limit of 10 batteries, chosen at random, and connected in series

2. Two supposedly identical machines are known to produce metal bars with a slightly different diameter. Machine A produces bars with a mean diameter of 12.32mm and a standard deviation of 0.77mm. Machine B produces bars with a mean diameter of 12.58mm and a standard deviation of 0.60mm.

If one bar is taken at random from each machine, what is the probability that the bar taken from machine A has a larger diameter than that taken from machine B?

Answer 1