Answer:
[tex]\begin{array}{ccc}cause&accidents&frequency\\pilot\ error&581&0.253\\human\ error&56&0.024\\weather&579&0.252\\mechanical&555&0.242\\sabotage&526&0.229\end{array}[/tex]
Pilot error, better training of pilots may reduce accidents.
Step-by-step explanation:
The total number of crashes is:
[tex]n = 581+56+579+555+526\\n=2297\ crashes[/tex]
The relative frequency is given by the number of accidents caused by each factor divided by the total number of accidents. The relative frequency distribution is:
[tex]\begin{array}{ccc}cause&accidents&frequency\\pilot\ error&581&0.253\\human\ error&56&0.024\\weather&579&0.252\\mechanical&555&0.242\\sabotage&526&0.229\end{array}[/tex]
The most serious threat to aviation safety is pilot error, a better training of current and future pilots could be a solution to reduce accidents.