Question
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 μ 19.8 minutes with a
standard deviation of 7.2 minutes. Assuming that
the distribution is approximately normal, find each of
the following probabilities.
a. What is the probability of randomly selecting
a student with a treadmill time greater than
25 minutes? In symbols, p(X 25) ?
b. What is the probability of randomly selecting a
student with a time greater than 30 minutes? In
symbols, p(X 30) ?
c. If the school required a minimum time of 10 minutes
for students to pass the physical education course,
what proportion of the freshmen would fail?
measured physical fitness for all high school freshmen.
During that time, the average score on a treadmill
endurance task has been μ 19.8 minutes with a
standard deviation of 7.2 minutes. Assuming that
the distribution is approximately normal, find each of
the following probabilities.
a. What is the probability of randomly selecting
a student with a treadmill time greater than
25 minutes? In symbols, p(X 25) ?
b. What is the probability of randomly selecting a
student with a time greater than 30 minutes? In
symbols, p(X 30) ?
c. If the school required a minimum time of 10 minutes
for students to pass the physical education course,
what proportion of the freshmen would fail?
Answers
PsyDAG
a. Z = (score-mean)/SD
Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability related to the Z score.
b, c. Same process.
Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability related to the Z score.
b, c. Same process.