SOLUTION: A company that has a large number of supermarket grocery stores claims that customers who pay by personal checks spend an average of $87 on groceries at these stores with a standar

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Question 1068696: A company that has a large number of supermarket grocery stores claims that customers who pay by personal checks spend an average of $87 on groceries at these stores with a standard deviation of $22. Assume that the expenses incurred on groceries by all such customers at these stores are normally distributed. What percentage of customers paying by check spend between $59.94
and $68.96 on groceries?

Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
z=(x-mean)/sd
=(87-59.94)/22=27.06/22=1.23
=(87-68.96)/22=18.04/22=0.82
Want the probability z is between those two values
p=0.0968 or 9.68%