SOLUTION: Assume the random variable x is normally distributed with mean = 86 and standard deviation = 4. Find the indicated probility p(x<80

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Question 1175747: Assume the random variable x is normally distributed with mean = 86 and standard deviation = 4. Find the indicated probility p(x<80
Found 2 solutions by amarjeeth123, ewatrrr:
Answer by amarjeeth123(569) About Me  (Show Source):
You can put this solution on YOUR website!
mean=mu=86
standard deviation=sigma=4
For a normal distribution z=(x-mu)/sigma
We can compute the probability using Excel.
We have to use a function called NORMDIST in Excel 2007.
The required probability=NORMDIST(80,86,4,TRUE)=0.066807201
Answer=0.066807201

Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!


0r 
one may use TI Calculator or similarly a $20 Casio fx-115 ES plus 
Normal distribution:   μ = 86 and    σ - 4

P(x < 80) = P( x ≤ 80 ) = normcdf(-9999, 80, 4, 86) = .06680720128
Commonly rounded to 4 decimals points 0r .0668