Air travel is probably not as fun as it used to be. Airlines have increased fares, reduced seat size, and now charge fees for everything from luggage to early boarding. Airlines can be fined by the federal transportation agencies for various "infractions". One issue subject to fines is consistently late arrivals and departures over scheduled times. Airline industry researchers believe charging passengers for luggage have resulted in passengers bringing larger and more luggage on board to avoid luggage fees. More on board luggage could potentially increase the amount of time it took to board all passengers and longer boarding times can result in delayed flights. A study was conducted to determine whether average boarding time was increasing. In previous studies conducted before baggage fees were implemented, average boarding time was recorded at 20 minutes with a known standard deviation of 5 minutes. In a recent sample (after fees) of 64 flights, the mean boarding time was determined to be 23 minutes. ANSWER THE FOLLOWING QUESTIONS: A. Perform the appropriate test at alpha = .05 to determine if average boarding times have increased.
What will be the z-score? please explain based on the example that I have because I know the formula but can you show me step by step. Thanks
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