SOLUTION: Household income does not tend to follow a normal distribution in a particular state, yet average income is approximately $45,000/year in this state, with a standard deviation of

Algebra ->  Percentage-and-ratio-word-problems -> SOLUTION: Household income does not tend to follow a normal distribution in a particular state, yet average income is approximately $45,000/year in this state, with a standard deviation of       Log On


   

Question 617130: Household income does not tend to follow a normal distribution in a particular state, yet average income is approximately $45,000/year in this state, with a standard deviation of about $9000. Within what income range would approximately 89% of the household incomes lie within this state? Show all work as to how this is obtained.
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
 

Hi, 

average income is approximately $45,000/year in this state, with a SD of about $9000.

using a normal distribution to approximate values that 89%  of houseolds lie

 1-.89 = .11, .11/2 = .055  Excel NORMSINV(.055)gives z = 1.59819

 1.59819 = (X -45000)/9000 

  X = 1.598*9000 + 45000 = $59,382

and

 -1.59819 = (x -45000)/9000 

x = -1.598*9000 + 45000 = $30,618