Test whether the average utility is faster using large sample test.
Nationwide, the average waiting time until electric utility customer service representative answers a call is 300 seconds per call. The Gigantic Kilowatt Energy Company took a sample of 35 calls and found that, on the average, they answered in 240 seconds per call with a standard deviation of 50. Can company claim that they are faster than the average utility?
1. No, because -0.20 falls in the critical region
2. Yes, because -7.10 falls in the critical region
3. No, because -1.20 falls in the critical region
4. Yes, because -0.20 falls in the critical region