Question

In a process that manufactures tungsten-coated silicon wafers, the tar- get resistance for a wafer is 85 mΩ. In a simple random sample of 50 wafers, the sample mean resistance was 84.8 mΩ, and the standard deviation was 0.5 mΩ. At 5% significance level, test whether the mean resistance of the wafers manufactured by this process is on target.