DB - Testing differences between population means :
Read the article, Passengers face airport weigh-in. Source: news.com.au, 2003.
Passengers face airport weigh-in
From correspondents in Washington
January 29, 2003
Passengers checking in for flights on small planes may be asked to step on the scales along with their baggage in a new US safety initiative.
As Americans' waistlines expand and they carry more luggage aboard, the Federal Aviation Administration (FAA) has decided to carry out a new survey of average passenger weights, a spokesman said.
The plan was prompted by the January 8 crash of a twin-engine commuter plane, which dived into an aircraft hanger seconds after take-off in Charlotte, North Carolina.
The plane exploded in flames, killing all 19 passengers and two crew.
The cause of the accident is still to be determined, but there has been speculation that one factor may have been the near maximum weight aboard and its distribution.
The National Transportation Safety Board is looking into the weight factor, leading the FAA to take "prudent" pre-emptive safety action.
Under existing rules, airlines may either weigh passengers individually, take their own survey of average passenger weights, or use average weights provided by a 1995 FAA advisory.
The FAA advisory is commonly used by airlines and estimates average passenger and carry-on luggage weights at 82kg in summer and 84kg in winter.
Check-in bags are presumed to weigh 12kg for domestic and 15kg for international flights.
"However, we realise that the weights of the people and of baggage are more critical to small airplanes with fewer seats," said FAA spokesman Les Dorr.
"As a prudent measure, we are asking the airlines that fly airplanes with 10-19 seats to validate the weights that they are using."
Within the next 30 days, 24 airlines operating a total of 223 planes with 10-19 seats would be asked to take a sample of 30 per cent of routes and check 15 per cent of those flights, he said.
Airlines could either ask the passengers to step on the scales or ask them to confess their own weight and then add a "fudge factor" of 4.5kg, along with weighing both carry-on and checked baggage.
The sampling must be taken within 30 days of Friday and be conducted at different times of the day on any consecutive Sunday, Monday and Tuesday.
"At the same time, FAA inspectors will be examining the airplanes involved in that sampling to check the condition of the restraint system for the checked baggage and the carry-on bags," Dorr said.
The results must be reported to the FAA at the end of the 30 days.
"Depending on what the results are, we will determine what additional action we have to take," Dorr said.
"It is important to understand that the NTSB has not said that is what caused the (North Carolina) accident. They are still looking at everything," he added.
"But we believe that as a prudent measure, recognising that perhaps the types of carry-on (baggage) have changed and we know that Americans as a class are getting heavier, we just thought it would a good time to see if we need to update the passenger and baggage weights that the airlines use."
Suppose you were a consultant who has been engaged by an airline company to estimate the 'fudge' factor for passenger's weights. Describe an experiment you would consider to estimate this 'fudge' factor. Discuss the statistical test you would consider using in this case.