SOLUTION: a) an experiment measures eye contact of a control group of people, during a 5 minute interval. What is the probability that a randomly selected person makes eye contact for >230

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Question 933890: a) an experiment measures eye contact of a control group of people, during a 5 minute interval. What is the probability that a randomly selected person makes eye contact for >230 seconds which is the mean for paranoid schizophrenics, during the five minute interval? Assume times are normally distributed with σ= 55 sec, μ= 184 seconds.
b) what is the value that separates off the lowest 10% of the eye contact times, from the upper 90%?
Answer by ewatrrr(24785) (Show Source):
You can put this solution on YOUR website!
μ= 184 seconds, σ= 55 sec.
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Person selected:
P( x > 230) = P(z > 46/55) = normalcdf(46/55, 100) = .2015 0r 20.15%
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P( .10 < x < .90) = P( -1.2816 < z < 1.2816) = normalcdf(-1.2816, 1.2816) = .8000 0r 80%
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