Question

PLEASE HELP!!! Flight times for commuter planes are normally distributed, with a mean time of 94 minutes and a standard deviation of 7 minutes. Using the empirical rule, approximately what percent of flight times are between 80 and 108 minutes?
32%
68%
95%
99.7%

Answer 1

Answer:

  95%

Step-by-step explanation:

The z-scores associated with the limits are ...

  z = (x -μ)/σ

  z = ({80, 108} -94)/7 = {-14, 14}/7 = {-2, 2}

That is, we're interested in flight times that lie within 2 standard deviations of the mean. The empirical rule tells us that 95% of the distribution lies within  2 standard deviations of the mean.