SOLUTION: Regal Cinemas commissioned a national study to determine the amount of money spent on concessions by their customers. The study revealed that the amount spent follows a normal dist

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Question 1012224: Regal Cinemas commissioned a national study to determine the amount of money spent on concessions by their customers. The study revealed that the amount spent follows a normal distribution with a mean of $6.11 and a standard deviation of $1.87.
(a) What proportion of all customers of Regal Cinemas spend more than $10.00 on concessions?
(b) What percentage of all customers of Regal Cinemas spend between $5.00 and $10.00 on concessions on a typical outing at the movies?
(c ) Determine the 90th percentile for money spent on concessions by Regal Cinemas customers.

Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
$6.11=mean
$1.87=SD
z>(10.00-6.11)/1.87=2.082
Proportion is 0.0188
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z for $5 is (5.00-6.11)/1.87=-0.5936
probability of z between -0.5936 and 2.082 is 0.7048
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90th percentile is z=1.282
Multiply by 1.87=2.40 above the mean.
$6.11+$2.40=$8.51