SOLUTION: The time spent watching tv on a weekend by USC students is normally distributed with a mean of 180 minutes and a standard deviation of 25 minutes. Find the probability that

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Question 1078255: The time spent watching tv on a weekend by USC students is normally distributed with a
mean of 180 minutes and a standard deviation of 25 minutes. Find the probability that
such a student selected at random will spend
(a) More than 230 minutes watching tv
(b) Less than 205 minutes watching tv
(c) Between 130 minutes to 155 minutes of watching tv
(d) More than 155 minutes of watching tv

Answer by stanbon(75887) (Show Source):
You can put this solution on YOUR website!
The time spent watching tv on a weekend by USC students is normally distributed with amean of 180 minutes and a standard deviation of 25 minutes. Find the
probability that such a student selected at random will spend
(a) More than 230 minutes watching tv
Find the z-value::
z(230) = (230-180)/35 = 50/35 = 1.4286
P(x > 230) = P(z > 1.4286) = normalcdf(1.4286,100) = 0.0066
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Use the same procedure::
Find the z-values ; then find the probability.
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Cheers,
Stan H.
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(b) Less than 205 minutes watching tv
(c) Between 130 minutes to 155 minutes of watching tv
(d) More than 155 minutes of watching tv