Final answer:
The principal cause of most accidents is human error, with driver error accounting for a significant percentage of fatal accidents. Factors like weather and road conditions contribute to accidents but are not the primary cause. Human error can also lead to accidents in industrial settings due to failure to follow instructions.
Step-by-step explanation:
The principal cause of most accidents is human error. Studies have shown that driver error is a significant factor behind fatal auto accidents. For instance, the American Automobile Association found that driver error accounts for approximately 54 percent of all fatal auto accidents. When a study of 30 randomly selected fatal accidents showed that 14 were caused by driver error, this can be used to test the accuracy of the AAA proportion using a hypothesis test at the alpha level of 0.05.
In different settings, such as industrial environments, accidents might also be caused by employees not following instructions. If a safety engineer is inspecting accident reports and considering the first report that indicates an accident caused by employee negligence as a 'success', this can be modeled using a geometric distribution, with the probability of 'success' being 35 percent based on her beliefs.
Other factors, such as weather conditions and road conditions, can also contribute to accidents, although they are often not the primary causes as compared to human error. For example, light rain can make roads slippery due to oil and gasoline leaks, affecting car control. Different animal species, such as squirrels, can sustain falls from heights that would typically injure humans due to differences in body structure and mass.