SOLUTION: A large department store has on average 448 shoppers in an hour, with a standard deviation of 21 shoppers. (i) What is the probability that a random sample of 49 different shoppin

Question 1171715: A large department store has on average 448 shoppers in an hour, with a standard deviation of 21 shoppers.
(i) What is the probability that a random sample of 49 different shopping hours has a sample mean between 441 and 446?
(ii) What is the probability that the store is packed with 500 or more shoppers in an hour?
Answer by Boreal(15235) (Show Source): You can put this solution on YOUR website!
the std deviation of the sample mean with 49 in a sample is 21/sqrt(49) or 3
z=(x-mean)/sd
for 441, the z value is -7/3; for 446, the z value is -2/3
the probability (and answer) is 0.2427
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for 500, z is (500-448)/21 or > 52/21. That probability is 0.0066.
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