Posted by **V** on Thursday, March 19, 2009 at 12:08pm.

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= x-the mean/sd but i am not getting a correct answer.

- Quantitative Methods -
**Reiny**, Thursday, March 19, 2009 at 12:55pm
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 z-scores (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**, Thursday, March 19, 2009 at 1:19pm
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

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