SOLUTION: Air Transportation data from 1969-1998 collected from www.air-transport.org Assume it is a binomial distribution (fatal vs not fatal) Year 1969 70 71 72 73 74 75 76 77 78 79 80

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Question 311235: Air Transportation data from 1969-1998 collected from www.air-transport.org Assume it is a binomial distribution (fatal vs not fatal)
Year 1969 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88
Accidents 7 2 6 7 6 7 2 2 3 5 4 0 4 4 4 1 4 2 4 3
Year 1989 90 91 92 93 94 95 96 97 98
Accidents 8 6 4 4 1 4 2 3 3 0
a.) Find the mean and standard deviation of the number of fatal air travel accidents in 1997. There were 8 million flights.
b.) Could a person claim that 8 fatal crashes in a year are unusual? Explain.
Answer by Fombitz(32388) (Show Source):
You can put this solution on YOUR website!
The mean is 3.73, the standard deviation is 2.1.
A value of 8 would give you a z-score of 2.03, a little greater than 2 standard deviations from the mean. I guess "unusual" is in the eye of the beholder and it would depend on your level of concern regarding airline travel. I would feel better if the mean was lower and the standard deviation smaller but I wouldn't think that 8 was unusual based on the data.