# help with calculating z-score.

• Jan 27th 2013, 09:54 PM
schia
help with calculating z-score.
Hello guys,
I have the answer here and need explanation on coming to terms with it. The question,

5000 apartments sold in a certain area and the mean price is \$459,000 and the standard deviation is \$76000. A particular apartment has a z-score of 3.78. What did it sell for? – The formula to calculate z-score is (x -mean) / standard deviation. The answer that I have from the text book is \$459,000+3.78*76,000=\$746,280… but why?

I've been punching in the numbers into the calculator and do not get \$746,280.

Any help is appreciated.

Regards
• Jan 27th 2013, 09:58 PM
schia
Re: help with calculating z-score.
BASIC MATH IDIOT MISTAKE... I should have did the multiplication before the addition.

Quote:

Originally Posted by schia
Hello guys,
I have the answer here and need explanation on coming to terms with it. The question,

5000 apartments sold in a certain area and the mean price is \$459,000 and the standard deviation is \$76000. A particular apartment has a z-score of 3.78. What did it sell for? – The formula to calculate z-score is (x -mean) / standard deviation. The answer that I have from the text book is \$459,000+3.78*76,000=\$746,280… but why?

I've been punching in the numbers into the calculator and do not get \$746,280.

Any help is appreciated.

Regards