People in hot - air balloons usually fly just above the treetops at between 250

Question

People in hot - air balloons usually fly just above the treetops at between 250 and 500 feet. In populated areas, however, they usually stay at an altitude of at least 1000 feet. The amount of flying time possible in a hot - air balloon is dependent on many factors: number of propane burners, number of people in the balloon, and weather. Assume the time spent aloft is normally distributed with a mean of 1.5 hours and a standard deviation of 0.45 hours. Approximately 20% of all hot - air balloon flights last less than _____ hours?

Explanation / Answer

z score corresponding to 20% area to its left = -0.84

Hence,

Approximately 20% of all hot - air balloon flights last less than (1.5 - 0.84*0.45) i.e. 1.122 hours.

Note - I have rounded the value to 3 decimal places. Please round it off as per the question demands.

Related Questions

Navigate

• Browse (All)
• Browse P
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.