In: Statistics and Probability
A sample of 64 resistors are taken from a production line and are found to have a sample mean of 998 Ohms. The population distribution for the resistances is unknown but the population standard deviation is known to be 10 Ohms.
(a) Find a 97% confidence interval for the population mean.
The tabulated value is and obtained from table.
Lower limit is and the upper limit is .
(b) Answer the following two questions by writing either ”narrower” or ”wider” in the blank space.
• If the sample size were increased to n = 1000 then the confidence interval would be than the confidence interval computed from a sample with n = 64.
• A 99% confidence interval is than a 97% confidence interval.