The US The Bureau of Labor Statistics reports that the average annual expenditure on food and beverages for a family is 

55700 (Noney. December 2003). Assume that the annual expenditures on food and beverages are distributed over

 

normal form and that the standard deviation is $1500.

 

to. What is the interval in which the expenses of the 10%o of the families that have the lowest annual expenses are found?

 

in food and drinks?

 

B. What percentage ( probability ) of families spend more than $7,000 annually on food and beverages?

 

c. What is the interval in which the expenses-averages of 5%o of the families that have the expenses

 

higher in food and drinks?

 

 

Exponential

 

2. The time to failure in hours of an ACME laser beam can be modeled by an exponential distribution with mean u = 30,000

 

to. What is the probability that a laser fails more than 15,000 hours?

 

b. What is the probability that a laser fails less than 20,000 hours?