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% ofall hot-air balloon flights last less than 4. hours? (5 points)

Answer 1

Solution:-

μ = 1.5, σ = 0.45

p-value for the 20% flights = 0.20

z-score for the p-value = - 0.841

By applying normal distribution:-

$z = \frac{x-\mu }{\sigma }$

x = 1.216

20% of all hot air ballon flights last less than 1.216 hours.