Posted by V on .
The monthly income of residents of Daisy City is normally distributed with a mean of $3000 and a standard deviation of $500.
a. What is the random variable?
b. The mayor of Daisy City makes $2250 a month. What percentage of Daisy City's residents has incomes that are more than the mayor?
c. Individuals with incomes of less than $1985 per monthe are exempt from city taxes. What percentage of residents is exempt from city taxes.
d. What are the minimum and the maximum incomes of the middle 95% of the residents
e. Two hundred residents have incomes of at least $4440 per month. What is the population of Daisy City.
I am using z= xthe mean/sd but i am not getting a correct answer.

Quantitative Methods 
Reiny,
I find this page very useful for these kind of problems.
http://davidmlane.com/hyperstat/z_table.html
The beauty is that you don't even have to enter the zscores (you can of course), but rather enter the mean and SD directly.
Since these kind of question rely on the use of tables or charts, I don't see any difference in using tables or a new type of application as this applet.
Let me know how it works for you
BTW, bobpursley answered the post just below this one for you yesterday. 
Quantitative Methods 
V,
i used the site (thx a bunch) but after i get the area i am confused as to how i get the final answer? the area for b is .066807 but i am not sure what to do next