Question 1156208: Over the past 10 years, the local school district has measured physical fitness for all high school freshmen. During that time, the average score on a treadmill endurance task has been = 19.8 minutes with a standard deviation of = 7.2 minutes. What proportion of students have a treadmill time less than 30 minutes?
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! Over the past 10 years, the local school district has measured physical fitness for all high school freshmen. During that time, the average score on a treadmill endurance task has been = 19.8 minutes with a standard deviation of = 7.2 minutes. What proportion of students have a treadmill time less than 30 minutes?
1st:: Find the z-score of 30
z(30) = (30-19.8)/7.2 = 1.417
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2nd:: Find the area under the normal curve below z = 1.417
Ans:: P(z<1.417) = normalcdf(-100,1.417) = 0.92
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Cheers,
Stanbon
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