scores of a standardized test are normaly distributed. Standard deviation is 4 points. what Sample size is needed to be 95%? confident sample mean 1 point of the true population mean.

Afactory buys 10% of its components from suppliers b and the rest from supplier c. it is known that 6% of the components it buys are faulty. of the components brought from suppliers a,9% are faulty and of the components bought from suppliers b, 3% are faulty. find the percentage of components bought from supplier c that are faulty.