A factory is making resistors. A normal batch has a mean resistance of 1000.0 ohms

A factory is making resistors. A normal batch has a mean resistance of 1000.0 ohms. A particular batch of resistors is sampled. The sample contains 20 resistors with a sample average of 1004.7 ohms and a sample standard deviation of 11.3 ohms.

a) To a 95 % confidence level, does this batch of resistors have different resistance different than normal?

b) To a 95% confidence level, does this batch of resistors have larger resistance than normal?

c) To what confidence level does this batch have larger resistance than normal?