a . is considered “ borderline .” b . is considered “ good ” and resides in an urban location . c . is suburban , given that customer is considered “ poor .” ( Points : 18 )
3 . ( TCO B ) Historically , 70 % of your customers at Rodale Emporium pay for their purchases using credit cards . In a sample of 20 customers , find the probability that
a . exactly 14 customers will pay for their purchases using credit cards . b . at least 10 customers will pay for their purchases using credit cards .
4 . ( TCO B ) The demand for gasoline at a local service station is normally distributed with a mean of 27,009 gallons per day and a standard deviation of 4,530 gallons per day .
a . Find the probability that the demand for gasoline exceeds 22,000 gallons for a given day .
c . How many gallons of gasoline should be on hand at the beginning of each day so that we can meet the demand 90 % of the time ( i . e ., the station stands a 10 % chance of running out of gasoline for that day )? ( Points : 18 )
5 . ( TCO C ) An operations analyst from an airline company has been asked to develop a fairly accurate estimate of the mean refueling and baggage handling time at a foreign airport . A random sample of 36 refueling and baggage handling times yields the following results .
Sample Size = 36 Sample Mean = 24.2 minutes Sample Standard Deviation = 4.2 minutes
a . Compute the 90 % confidence interval for the population mean refueling and baggage time . b . Interpret this interval .
c . How many refueling and baggage handling times should be sampled so that we may construct a 90 % confidence interval with a sampling error of . 5 minutes for the population mean refueling and baggage time ? ( Points : 18 )