Interpret a probability of 0.002 of an event occurring in terms of odds (one in

Interpret a probability of 0.002 of an event occurring in terms of odds (one in some value, such as 1/10).  Compare this to a probability of 0.20 of an event occurring in terms of odds.  Which one is a statistically significant event, and which one is not a statistically significant event?  Explain your reasoning. 
Describe the process for making a tree diagram and give an example. 
What important question must you answer before computing an “or” probability? How does the answer influence your computation? Use a diagram or equation to help explain your answer. 
The probability of a randomly selected car crashing during a year is 0.0423 (based on data from the Statistical Abstract of the United States). If a family has three cars, find the probability that at least one of them has a crash during the year. Is there any reason why this probability might be wrong?